The Effectiveness of Public and Private Signals:A Document-Based ApproachAzusa Katagiri and Eric Min∗

Weatherhead Center for International Affairs, Harvard Universityand

Department of Political Science, Stanford University

May 29, 2017

AbstractCrisis bargaining literature has predominantly used formal models and qualitative studies todebate the relative efficacy of actions, public words, and private words. These abstract andretrospective approaches have precluded scholars from considering the reality of the informa-tional environment during crisis bargaining. Policymakers are bombarded with informationand struggle to adduce actual signals from endless noise. As such, events are more effectivethan any diplomatic communication in shaping elites’ perceptions. However, an additionalconsequence is that private messages, despite being ostensibly “costless,” provide a channelfor more precise communication than public and potentially “costly” pronouncements. Over18,000 documents from the Berlin Crisis of 1958-1963, reflecting private signals, public signals,and White House evaluations of Soviet resolve are digitized and processed using statisticallearning techniques to evaluate these claims. Results indicate that events have substantiallygreater influence on White House beliefs than either public or private signals; that publicsignals are noisier than private communications; and that private signals have a relativelylarger effect on evaluations of resolve than public statements. These findings, based on auniquely systematic, comprehensive, and fine-grained analysis of text data, have substantialimplications on contemporary theories of diplomacy and crisis management.

∗Authors’ e-mails: akatagiri@wcfia.harvard.edu and ericmin@stanford.edu. Names are in alpha-betical order. We thank Ken Schultz, Jim Fearon, Scott Sagan, Justin Grimmer, Janet Box-Steffensmeier,Jeffrey Friedman, Robert Gulotty, and the participants of the 2015 Annual Meeting of the Society for Po-litical Methodology (Rochester, NY), 2015 Annual Meeting of the American Political Science Association(San Francisco, CA), 2017 Annual Convention of the International Studies Association (Baltimore, MD),and 2017 Annual Meeting of the Midwest Political Science Association (Chicago, IL) for their thoughtfulcomments. Azusa Katagiri also acknowledges the support of the Suntory Foundation. Eric Min furtherexpresses gratitude for the financial support of the National Science Foundation’s Graduate Research Fel-lowship #DGE-114747. Lastly, we both thank the Stanford Institute for Research in the Social Sciences.All errors are our own.

1 IntroductionScholarship on international relations has fervently discussed the differing effects, if any, betweenpublic and private diplomacy. Following the work of Schelling (1966), scholars have broadly ac-cepted that the credibility—and thus effectiveness—of threats made during crises is tied to thecostliness of the gesture made to express it. It is rather unsurprising that highly visible actions,such as mobilizations, troop movements, or blockades, consume substantial resources and time aremost likely to influence a target audience’s belief that the sender is seriously willing to engage inhostilities to achieve its objective. However, despite the memorable nature of such events, they arerelatively infrequent. Much of the everyday administration of interstate diplomacy never rises tosuch dramatic heights, but instead remains in the realm of verbal exchanges.

In the last two decades, audience cost theory (Fearon 1994, 1997; Smith 1998; Schultz 2001; Tararand Leventoglu 2012) has extended the logic of costly signals to this more peaceful arena, sug-gesting that public statements carry more weight by means of tying hands thorough highly visiblecommitments, since the party making the statement would suffer costs for backing down (Schelling1960; Snyder 1972). While these theories were originally developed with crisis bargaining in mind,subsequent research has extended the logic of using audience costs as bargaining leverage morebroadly (Leventoglu and Tarar 2005). In this framework, diplomatic communication that occursout of general view in the early stages of crises is relatively cheap, as actors suffer fewer sanctionsfor making claims that they do not see through.

On the other hand, some recent scholarship has suggested that privately relayed messages are notalways cheap. A bevy of work has challenged the general premise, utility, and/or empirical tests ofaudience cost theory (Snyder and Borghard 2011; Trachtenberg 2012; Downes and Sechser 2012).Diplomacy out of public view may be effective because it allows leaders to back away from warwithout suffering domestic costs (Kurizaki 2007), because states develop and care about reputationsfor being honest (Sartori 2002, 2005), because they still allow for actors to coordinate actions andobtain some information (Ramsay 2011), or because a party could reveal the communicationspublicly as a punishment if an initial signal proves false (Yarhi-Milo 2013). Private signals, despitetheir relative lack of costs, are also advantageous in allowing parties to search for compromisewithout recklessly committing themselves to very visible threats that force war (Leventoglu andTarar 2008; Trager 2010). Despite the active nature debate on the relative efficacy of public andprivate diplomatic actions, few empirical studies beyond formal models and surveys have firmlyput this comparison to a test.

In this paper, we use the Berlin Crisis of 1958-1963 as a testing ground for theories of diplomacy.Full sets of declassified documents provide a detailed, comprehensive, and uncensored view of theUnited States government’s evaluations of threat during this period, which was arguably one of themore dangerous times for American if not global security. We digitize, process, and analyze over18,000 documents from the Department of State, Foreign Broadcast Information Service, and WhiteHouse to create dynamic data on private and public diplomatic signals sent from the Soviet Unionand East Germany to the United States, as well as a measure of American evaluations of Sovietintents with respect to Berlin. These weekly-level data allow for a uniquely detailed investigationof conflict dynamics that other studies have been unable to accomplish.

The new resources collectively paint a picture that challenges some primary facets of contemporarycrisis bargaining theory. The intense scholarly debate about the relative effectiveness of public andprivate signals may be overstated. In the shadow of provocative material events, neither public nor

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private signals prove to have a substantively noteworthy effect on shaping American perceptions ofthreat. These results speak to the importance of seriously considering the informational environ-ment in which crisis bargaining occurs—one that is defined by tremendous volumes of informationthat make it difficult to separate real signals from the noise of everyday governance. In such afrenzied setting, private signals are a more direct and concise manner in which states can commu-nicate. The ability to ostensibly tie one’s hands through a public statement is undermined by therelatively higher degree of noisiness that these public messages entail. We show that, contrary tocommon expectations in international relations literature, private signals are more effective thanpublic signals in affecting perceptions of threat.

Overall, this study presents the first systematic and quantitative analysis of the intricacies ofcrisis diplomacy. The methods used here establish a framework that can be applied to othercrises, opening the door to more empirically-driven scholarship on the machinations of interstateinteractions.

In Section 2, we summarize the extant literature on crisis bargaining before outlining how a morepractical understanding of the quantity and quality of diplomatic information affects current the-ories. In Section 3, we establish the elements necessary to test our hypotheses and provide a briefsummary of the Berlin Crisis. Then, we describe three new sets of diplomatic data that capturepublic signals, private signals, and elites’ perceptions of both over this five-year period. Section 4presents results of the statistical analysis using these time-series data. Section 5 concludes.

2 Diplomatic Signals in Theory and PracticeMost crisis bargaining literature, whether emphasizing public or private diplomacy, focuses onspecific moments in which a tense situation may escalate into more overt hostilities. Formal ap-proaches, which dominate this field of study, almost exclusively create models that begin with arevisionist party expressing a desire to change the status quo and a willingness to do so throughthe use of force. The other party is then left to make a concession or to remain resolute, inchingthe interaction closer to armed conflict.

The escalatory nature of crisis bargaining is predicated on the issuance and interpretation of threats.Threats are messages designed by one party to signal its capabilities and intention to cause harmto the other party if it does not comply with some expected behavior (Singer 1958; Stein 2013).1

More recently, crisis literature speaks of the interaction between capabilities and resolve, where thelatter broadly represents an actor’s willingness to use force (Fearon 1992; Huth 1988). A threat ismore likely to be considered credible, and thus more able to influence future behavior, when it issupported by high physical capabilities, high resolve, or both. The predominant understanding ininternational relations is that signals sent in public will convey greater credibility through resolvethan those made in private because of the alleged costs that the sender would suffer to renege onits threat (Fearon 1994; Schelling 1966). Most evidence in support of this hypothesis is found informal models.

A small handful of survey and experimental research has provided some insights on the efficacyof public and private signals (Tingley and Walter 2011; Tomz 2007). Even so, these approachesmay fail to be generalizable and tend to impress the issue upon individuals that have never had to

1It is worth noting that this “Threat = Capabilities × Intent” framework has heavily permeated policymakingcircles and continues to influence them today (Steury 1996; Cross et al. 2013).

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contemplate foreign policy decision-making with enormous time pressure and national interests atstake, and whose perceptions regarding crises may not be as relevant to actual decision-making.2

Statistical approaches using observational data adopt a similar strategy by using a crisis event asthe main unit of analysis—consider the MIDS, the Militarized Compellent Threat, the InternationalCrisis Behavior, or Huth and Allee’s Territorial Dispute datasets. Each of these resources capturesdiscrete incidents that could plausibly become flash points for war. Quite recently, McManus (2014)looks at U.S. presidents’ public statements of resolve during militarized interstate disputes and findsthat public statements do have an effect on success.3

Despite the utility of these various empirical approaches, they all overlook several essential issuesrelated to the concept of information. A fundamental problem is that these data and methodsimplicitly assume that the parties share a mutual understanding that they are in the midst of adiscrete crisis event. For this to be the case, informational signals sent by the involved partiesmust be communicated with great frequency and/or clarity, at least to the extent that a receiverinterprets a challenger’s action to be a threat that deserves attention, and enacts a strategic responsethat the challenger would also understand to be part of this specific interaction.4 In other words,signals must be stronger than any surrounding noise to the extent that all potentially involvedparties are aware that they are clearly in the midst of a crisis, and to navigate it appropriately.The degree to which policymakers accomplish this goal are a function of the quantity and qualityof the information that they receive.

2.1 QuantityMost studies of crisis bargaining presume that the incident in question occurs in a vacuum, andthat no other concerns are salient to policymakers. This seems innocuous when focus is inherentlyplaced on crises as the unit of analysis. Such simplifications also help to make theorizing moretractable and bring interesting dynamics into the spotlight. However, these events, when they dooccur, are only temporary jolts in the midst of constant bureaucratic, political, and administrativework. Activity will likely increase during overtly grave situations, such as when Kennedy allocateda substantial amount of time to the Berlin issue during its most threatening moments in July 1961(Slusser 1973, 77). But by ignoring the nature of everyday business, crisis scholarship glosses overthe fact that policymaking is constantly active and alert to potential signs of trouble or opportunity.Of 172 meetings of the National Security Council between 1958 and Kennedy’s assassination inNovember 1963, only 13 (about 7%) involve explicit discussion of Germany or Berlin. Moreover,of these 13 meetings, only two focus solely on this topic; the other 11 include additional matters.While many information-based models of interaction assume that signals sent are clear (in that thereceiver understands a signal to be a signal, regardless of how hazy it may be) and receive vigilantattention, actors typically struggle to simply keep their heads above the water (Brzezinski 1983).Not only do elites have too much information to process with respect to one issue, but they are alsohard-pressed to manage time for many issues at once. Kissinger (1979) makes this point explicitly:

But the old adage that men grow into office has not proved true in my experience. Highoffice teaches decision-making, not substance. Cabinet members are soon overwhelmed

2Mintz et al. (2006) provide experimental evidence of the divergence of responses between college students andmilitary officers.

3However, the study does not speak to private diplomacy.4Furthermore, datasets of crises moments likely suffer from selection bias, as only cases where tensions sufficiently

escalated will be observed and recorded, while incidents resolved behind closed doors are not.

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by the insistent demands of running their departments. On the whole, a period in highoffice consumes intellectual capital; it does not create it.... The novice Secretary of Statethus finds on his desk not policy analyses or options but stacks of dispatches which heis asked to initial and to do so urgently, if you please. He can scarcely know enoughabout all the subjects to which they refer, or perhaps about any of them, to form anopinion (30-31).

When we strip away the notion that diplomatic interactions are a series of discrete and conspicuouscrises, we are left with a more frenetic environment where elites perpetually strain to surmise theintents of potential adversaries by attempting to filter useful signals out of diplomatic noise. It isnot immediately clear when or why another state will engage in hostile and escalatory behavior.Inevitably, some inauspicious predictions based on purposeful observation and analysis may beproven incorrect later, while some real problems may not be predicted and later surprise policy-makers (Snyder and Diesing 1977). Both false positives and false negatives could seem obvious andeven puzzling in retrospect. Yet in the moment, the disorderly and overwhelming informationalclimate that characterizes policy-making makes deductions difficult and errors inevitable.

In an important book, Wohlstetter (1962) argues that the attack on Pearl Harbor was not preventedbecause the United States government could not properly distinguish signals, which included actualdecoded information on Japanese plans, from the noise of contradictory information that constantlybombarded the policymaking elites. Simply put, “There was as much noise as there were significantsounds” (228). Wohlstetter aptly describes the chaotic climate:

The imagination staggers at the spectacle of the blocks in the way of information thathad to travel a longer or more tortuous and less protected path. Inevitably in the dinof jurisdictional battle, interoffice and interdepartmental memos, opposing estimates ofthe situation, and rival views of the value of the risk, the essential item was sometimeslost. The large number of particles of information that penetrated all barriers to arriveat those “who need to know,” the decisionmakers, is not only something of a miracle,but also bears testimony to the still greater number that started on the journey andnever arrived. For there was no single person or agency in Washington that had all thesignals available at any one time (229).

Intelligence communities of both scholarly and policymaking backgrounds are acutely concernedwith the ability to filter signals from noise, which is commonly referred to as “the Roberta Wohlst-stter problem” (Dahl 2013; Zarate 2009).5 Finel and Lord (1999) indicate that governmentaltransparency does not alleviate crises by providing more information, but rather exacerbates themby flooding the environment with noise that does not equally reflect a state’s official policies orpositions. Related notions are found in administrative, psychological, and technology scholarshipon “information overload,” which investigates the effects of increasing access to information—particularly due to technological advances such as tapes, computers, and the internet—on theability of individuals to absorb knowledge (Downs 1972; Edmunds and Morris 2000; Kahneman1973; Simon 1947, 1971). In an environment where individuals and organizations have access to farmore information than they could see or understand, “attention” becomes a scarce and valuable re-source (Falkinger 2007, 2008; Huberman and Wu 2008). The enormity of information and potentialpriorities forces decision-makers to engage in selective attention and incomplete updating (Jonesand Baumgartner 2005; Yarhi-Milo 2014). Importantly, governmental agencies using telegrams and

5The September 11 attack brought this issue back to the forefront. The 9/11 Commission Report also makesheavy reference to Wohlstetter’s work.

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other near-instantaneous forms of communication have dealt with large volumes of information farearlier and to a greater degree than the average individual.

These observations regarding the everyday administration of national affairs may seem like unnec-essary details or marginal concerns that a model of diplomacy could justifiably simplify away. Butthe points made thus far suggest that past analysis and theorizing may be overestimating whateffect diplomatic signals have on perceptions of resolve in the midst of crises. Scholars may haveplaced undue importance on public and private diplomatic signals during crisis moments, partic-ularly when studying such events in an ex post manner where hindsight allows us to more clearlyidentify threatening events. Both must play some role in shaping elite perceptions, or else theexistence of diplomatic institutions would be exceedingly ill-justified.

That being said, elites that are surrounded in a flurry of communications will struggle to adequatelyfilter and process each signal that emanates from a particular source. In these cases of informationaloverload, elites may primarily rely on another agent’s non-diplomatic actions—costlier in reputa-tion, resources, and time—to divine their intentions. We would thus expect that policymakers’beliefs are more greatly affected by actions rather than any words. Such is the first hypothesis:

Hypothesis 1 Public and private diplomatic signals both have smaller effects on evaluationsof resolve than actions.

It is almost certain that publicly provocative events will have a greater impact on elites’ beliefs thanwords alone. Nonetheless, this is an assertion worth systematically testing, and it also provides areference point through which we can contextualize the effects of public and private signals. Notethat our contention is not that diplomatic signals are wholly irrelevant to shaping perceptions ofresolve. Rather, we are suggesting that the effect of either channel is far more attenuated thanmany qualitative and formal studies of crisis diplomacy would suggest.

2.2 QualityWhile Hypothesis 1 predicts that public and private signals are less influential on elites’ beliefs thanactions, this does not suggest that both forms of diplomatic communication are equally (in)effective.Audience cost theory finds that public statements are better suited to tie leaders’ hands and thusgenerate more costly commitments that the adversary would recognize as being credible (Fearon1994; Schelling 1966). However, in a more realistic diplomatic environment that is consistent withour previous discussion, public signals feature two characteristics that complicate this assertion.

First, and related to the previous discussion, public pronouncements are enormously high in volume.The Central Intelligence Agency’s Foreign Broadcast Information Service (FBIS), to which wereturn later, was established to translate collect all publicly available information such as radiobroadcasts, speeches, and press articles emanating from adversarial nations (Roop 1969). Just forthe issue of Berlin alone, the FBIS records over 10,700 entries from the Soviet Union between 1958and 1963.

Second, public signals are unclear. Open pronouncements, regardless of their intended demographic,may be observed by one’s own fellow elites, one’s own citizens, the adversary’s government, the ad-versary’s citizens, other international governments, and other international citizens. Each of these

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groups is liable to view and misinterpret a message that was intended for another constituency.6

These messages, which may be contradictory and/or ambiguous as a regime attempts to walk atightrope above multiple audiences, all run through the same pipeline. This makes their interpre-tation difficult, even if we were to generously assume that all actors were fully attentive to a singlecrisis event.7

Highly public actions that turn the tide of a crisis may be easier to identify in retrospect, butthey are not as easy to understand when in the midst of escalatory interactions. In these cases,governments can turn to private diplomatic signals to send direct, clearer, and more selectivemessages of intent. Diplomatic communities emphasize the importance of the tete-a-tete—privateand candid conversations between two people—as a manner to communicate without distractionsor political theater (Perlmutter 1975; Russell 2000).8 This exact line of reasoning motivated thenow-famous exchange of letters between President Kennedy and Chairman Khrushchev in late 1961,as both leaders attempted to address immense anxieties and escalating rhetoric regarding Berlin.Responding to Khrushchev’s initial letter on September 29, Kennedy wrote back the following onOctober 16:

I am gratified by your letter and your decision to suggest this additional means of com-munication. Certainly you are correct in emphasizing that this correspondence must bekept wholly private, not to be hinted at in public statements, much less disclosed to thepress. For my part the contents and even the existence of our letters will be known onlyto the Secretary of State and a few others of my closest associates in the government.I think it is very important that these letters provide us with an opportunity for apersonal, informal but meaningful exchange of views. There are sufficient channels nowexisting between our two governments for the more formal and official communicationsand public statements of position. These letters should supplement those channels, andgive us each a chance to address the other in frank, realistic and fundamental terms.Neither of us is going to convert the other to a new social, economic or political pointof view. Neither of us will be induced by a letter to desert or subvert his own cause.So these letters can be free from the polemics of the “cold war” debate. That debatewill, of course, proceed, but you and I can write messages which will be directed onlyto each other.

A slightly more detailed historical anecdote may provide more evidence. On October 20, Kissingerarrived in Moscow and agreed to establish a ceasefire to stop the Yom Kippur War which haderupted two weeks earlier. Kissinger met with Israeli Prime Minister Golda Meir and her cabinettwo days later to persuade Israel to accept the terms. The next day, Israel had appeared to ignorethe ceasefire and was proceeding to encircle the Egyptian Army—an event that both the Americansand Soviets had sought to avoid. Kissinger feared that the Soviets would see this as a purposefulact of deception to aid the Israelis (Blechman and Hart 1999). Indeed, the Soviets alerted theirforces, and Brezhnev publicly stated that the USSR would unilaterally impose a ceasefire if theUnited States chose not to join the effort. A series of naval confrontations in the Mediterraneanbetween American and Soviet ships also heightened tensions in the sea, especially given intelligence

6Clare and Danilovic (2010) and Trager (2015) speak to the additional strategic dimensions involved when dealingwith multiple audiences.

7Although the Soviet Union was non-democratic, we emphasize that their public statements should not be seenas costless or low in costs. Public signals could potentially affect international reputation, and Soviet elites in thePresidium of the Central Committee wielded the power to push Khrushchev out of power if they wished (and whichbecame the case in 1964). See Weeks (2008) for further discussion of non-democratic audience costs.

8In French, tete-a-tete literally means “head-to-head.”

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indicating that a Soviet ship was carrying radioactive material.

At 11:41 P.M. on October 24, Nixon’s administration publicly put all military commands on highalert—DEFCON 3—with the aim of showing American resolve to the Soviets (Sagan 1985). By themorning of October 25, the global DEFCON 3 was being widely reported in the media (Kissinger1982). Brezhnev and the Politburo were perplexed by this seemingly unprovoked action. Despitehis rhetoric, Brezhnev had no intent of directly engaging in conflict or placing troops in Egypt.He incorrectly believed that this threat, originally a bluff, had been clarified. Many of the puzzledSoviet leaders concluded that Nixon’s alert was designed for domestic political purposes (to showresolve to citizens and to distract from the unraveling Watergate ordeal), while others underesti-mated the severity of a DEFCON 3 alert (Lebow and Stein 1994). Had it not been for Brezhnev’spersonal opposition toward military escalation, the Politburo was likely to have mobilized greaternumbers of forces in response to the nuclear alert. Although the standoff was soon resolved throughprivate communications, the Soviets remained upset and confused by what had transpired. Warwas avoided despite the fact that public signals had been misinterpreted in both directions.

Kurizaki (2007) points out that centuries of private, if not secret, diplomatic interactions challengethe idea of costly and hand-tying signals. Several scholars have also made the case that privatediplomacy can engender costs because states care about their reputations for honesty (Guisingerand Smith 2002; Sartori 2002, 2005) and because they want to avoid being called out for duplicity(Yarhi-Milo 2013).9 Our argument adds another dimension. While these studies still assumeconsistent interpretation of signals in service of resolving a crisis, we suggest that public signals arealso less clear and more difficult to track than private ones.

Overall, private signals may therefore be relatively more effective than public statements. Thisargument rests on an observable mechanism: public signals should be more varied in their messagesacross signals. The need to cater to multiple audiences will cause elites to produce an enormousnumber of public signals that, when considered together, generate a noisier overall impressionthan that produced through private channels alone.10 Even if a message is intended for a specificrecipient, the nature of public statements allows all others to also see and interpret those signals,so the sender must exercise caution.

This discussion points to two related hypotheses.

Hypothesis 2 Public signals feature greater variance across signals than private signals.

Hypothesis 3 Private signals are relatively more effective than public signals in shapingevaluations of resolve.

The theoretical foundation of Hypothesis 2 is, to our knowledge, unique in contemporary theoriesof crisis bargaining. Although some scholars have pointed out that diplomatic signals are generallyharder to interpret than many rationalist theories presume (Barston 1988; Lebow 2001), no relativedistinctions of this sort have been made between public and private channels. Most theoretical

9We note that Guisinger and Smith (2002) and Sartori (2002, 2005) do not make an explicit distinction betweenpublic and private diplomacy, but instead discuss costly (militaristic) and costless (diplomatic) signals during crises.Nonetheless, their ideas readily extend to a contrast between public and private forms of diplomacy. This is theframework adopted by subsequent research (Baum 2004; Kurizaki 2007) and is also more consistent with the languageused in audience cost literature.

10By ambiguity, we refer to an intentional attempt to keep a message open to interpretation. See Scott (2001).

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arguments regarding the relative merits of public and private diplomacy tend to be based on fullystrategic notions such as hand-tying and maintaining one’s reputation. Little to no emphasis isplaced on practical and inadvertent considerations of diplomatic signaling.

Perhaps due to the compellingly intuitive strategic logic of public hand-tying, even scholars pro-moting the importance of private diplomacy only claim that private communications can be just aseffective as public ones under certain circumstances. Our focus on the noisiness of signals providesa basis for Hypothesis 3, which goes further in claiming that private signals are generally moreeffective in altering elites’ perceptions.

3 DataWe evaluate our hypotheses by studying the interaction of three large sets of documents thatdirectly correspond with public diplomacy, private diplomacy, and internal policymaking deci-sions/deliberations. Specific focus is placed on the Berlin Crisis between 1958 and 1963.

3.1 The Berlin CrisisThe Berlin Crisis was possibly one of the most serious periods of sustained tension in the lastcentury. The struggle over Berlin engendered serious concerns about the outbreak of nuclear war.

After the conclusion of World War II, four victorious powers—the United States, the United King-dom, France, and the Soviet Union—divided the German capital city of Berlin into four sectors.The Soviet sector stood alone as East Berlin, while the remaining three were collectively consideredWest Berlin. The remainder of Germany was also split on similar terms. However, Berlin (and thusthe Allies’ West Berlin) lay deeply embedded in East Germany, more than 100 miles behind Sovietlines. The Western powers originally established a presence in Berlin because they assumed thatall of Germany would be overseen collectively. However, mounting Cold War tensions increased thesalience of the boundary between West and East Germany and made Western presence in Berlinincreasingly troublesome and geographically symbolic (Trachtenberg 1999).

For many years after, but especially between 1958 and 1961, the right of Western access to WestBerlin was treated as a fundamental testing ground of resolve. In a letter to Secretary of StateJohn Foster Dulles, the American ambassador to West Germany, James B. Conant, went as far asto call Berlin a “superdomino” for which American weakness would reverberate across the entiretyof Germany and Europe (Office of the Historian 1992, 376-381).

The Western allies began efforts to reform West German currency in 1948. At that time, theSoviet Union initiated a blockade that closed ground routes in and out of West Berlin, forcing thethree allies to deliver supplies using the Berlin airlift. In 1949, the Western allies helped found theFederal Republic of Germany, or FRG (which technically excluded West Berlin, even though thesesectors publicly aligned themselves with the West), and the Soviets helped establish the GermanDemocratic Republic, or the GDR. The GDR declared its capital to be East Berlin—a decision theWestern powers considered provocative and refused to recognize. The FRG established its capitalin Bonn.

Restricted access to West Berlin underlined much of the escalated tension between 1958 and 1963,

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which define a broader definition of the Berlin Crisis.11 Leading up to 1958, Khrushchev hadgrown weary of diplomatic tap-dancing regarding Berlin, which appeared to be going nowhereKempe (2011). On November 10, 1958, Soviet Premier Khrushchev made his first ultimatum onBerlin, granting Eisenhower and the Western allies six months to withdraw from and demilitarizetheir share of Berlin (Williamson 2012). If this did not occur, the Soviets would turn all lines ofcommunication and control over to East Germany—a party known to be more recalcitrant thanthe Soviet Union, which could threaten all Western access to West Berlin.12 As early as March1959, Acting Secretary of State Christian Herter (working in the stead of an ailing John FosterDulles) indicated that the United States would have to issue the “ultimate threat” of nuclear warto defend its interests in Berlin (Burr 1994).

By May of 1959, the Western allies had remained resolute, and Khrushchev had withdrawn hisultimatum. A meeting of the four foreign ministers in July failed to make significant progress onthe Berlin question, but ended on a note of mutual desire for a peaceful resolution to be furtherdiscussed at a Paris summit planned for May 1960. However, due to the U-2 Incident on May 1, inwhich an American reconnaissance plane was shot down over Soviet territory, this meeting neveroccurred (Barker 1963).

The Kennedy administration took office in January 1961 and initially adopted a reactive stanceon Berlin. A meeting in Vienna between Khrushchev and Kennedy on June 4, 1961, startedon friendly terms but quickly devolved when Khrushchev, according to Kennedy himself, “wentberserk” (Smyser 2009, 65). This resulted in a second Soviet ultimatum: If the Western allies didnot immediately agree to a peace treaty proposing reunification on Communist terms, the SovietUnion would sign a separate peace treaty with East Germany, fully cutting off access to WestBerlin.13 It was by this time that Berlin contingency planners seriously discussed the possibilityof nuclear weapons (Williamson 2012, 215). On July 25, 1961, President Kennedy even made atelevision report to the nation in which he explained Soviet attempts to cut off access to WestBerlin, bringing up the imminent threat of nuclear war and discussing measures to make sure thatall American citizens have access to fall-out shelters.14

On August 12, 1961, East Berlin mayor Walter Ulbricht authorized an order to close the borderbetween West and East Berlin and to create a wall, stemming large westward migrations of EastGermans (Harrison 2011). A barbed wire fence stretched across the border would later be replacedwith the notorious concrete barrier.

In the following months, American forces would experience harassment at checkpoints that crossedbetween East and West Berlin. A slowly escalating trend of checkpoint activity, often resembling agame of chicken, boiled over at Checkpoint Charlie on October 22, 1961. Three days of posturingpeaked when Soviet and American tanks sat pointed at one another, 100 yards apart, before both

11Many references solely focus on late 1961 as the Berlin Crisis. However, we use the somewhat more “liberal”view, which treats Khrushchev’s ultimatum as the key trigger event. Subsection 4.4 shows that our main findings areequally valid for this shorter period.

12Zubok (1993) refers to primary documents in order to conclude that this declaration was “ninety percent im-provisation” (12), apparently uttered with hopes to still resolve the German issue peacefully. Barker (1963) alsomakes this assessment, even without the advantage of retrospection. However, the Soviet Union subsequently send adiplomatic note to the Western allies formally restating these terms on November 27 (Newman 2007).

13While the Western powers maintained a resolute position regarding access to West Berlin, Kennedy underminedhimself by suggesting the the US was open to a permanent division of Berlin. This move made his subsequentstatements less credible to the Soviets (Carmichael 2011).

14Note that this address occurs more than a year before the Cuban Missile Crisis, as well as one month beforeconstruction begins on the Berlin Wall.

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sides backed down. This stand-off was one of the most dangerous moments of the Cold War, atleast in Europe (Trauschweizer 2006).

From late 1961 through 1962, the United States government engaged in sporadic negotiations withboth its Western allies (who often did not see eye-to-eye) as well as the Soviets. In January andMarch 1962, Secretary of State Dean Rusk met with Soviet Foreign Minister Andrei Gromyko ina series of abortive talks, and attempts to negotiate a solution effectively ended by the summer.The Soviet Union’s retreat from the Cuban Missile Crisis, which followed months later, irrevocablydampened Khrushchev’s clout and diluted Soviet diplomatic leverage regarding Berlin. This lossof face helped remove remaining obstacles to the Limited Nuclear Test-Ban Treaty, a years-longeffort that had been held up by both parties linking concessions to the Berlin question. The treatywas signed on August 5, 1963 and went into effect on October 10, 1963.15 Although the wall wouldnot fall for another 36 years, the most heightened period of tension regarding Berlin had passed.

This relatively brief overview indicates at least two reasons why the Berlin Crisis is an ideal casefor studying crisis diplomacy. First, this five-year period is one of substantial historical import,punctuated by multiple moments that could have potentially sparked major hostilities if not theuse of nuclear weapons. Although the term “Berlin Crisis” suggests a single period of hostility, thetime span is much better characterized by several distinct and significant flash points, as well assustained periods of relative calm, that each provide evidence on the different effects of public andprivate diplomacy during the everyday administration of policy-making. Moreover, even thoughthe average level of perceived resolve by American policymakers during this time may be consideredconstant (and perhaps higher than usual), actual perceptions of threat clearly fluctuate over time,even at the qualitative level.16 Second, studying the Cold War and a location that served as aclear geographical and symbolic focal point for this period provides a best-case scenario for findinglarger effects of diplomatic signals in shaping perceptions.

Due to the passage of several decades, the Berlin Crisis is also well-documented in archival collec-tions and is almost fully de-classified due the passage of several decades.17 This allows us to obtaina comprehensive set of documents that reflect the uncensored and instantaneous thoughts of in-dividuals in the United States policymaking elite, without retrospective, censorship-based, and/orhistorical biases. To our knowledge, this sort of comprehensive document-based approach does notexist in security studies.

3.2 Data SourcesBeyond non-verbal events, our investigation relies on evaluations of resolve within three facetsof crisis diplomacy: private signals, public signals, and elites’ subsequent perceptions of both.Comprehensive diplomatic records provide the ideal resource to systematically track these concepts.Although they may seem difficult to disaggregate, several sources of archival documents are alreadysorted into these general categories.

Private diplomatic signals are captured through de-classified telegrams from the U.S. Departmentof State. Almost all of the documents were obtained at the National Archives II in College Park,

15In October 1964, Khrushchev was quietly deposed and replaced by Brezhnev.16This is borne out by data later in the text.17Documents such as those used in this paper are mostly de-classified up until 1978. However, due to the dilatory

nature of declassification, many documents on Berlin were only released in the last two decades, and a substantialcollection of highly sensitive materials were released in 2011, of the fiftieth anniversary of the Berlin Wall.

10

Maryland.18 These collections predominantly involve incoming messages from the United StatesEmbassies in Bonn and Moscow, as well as the U.S. Mission Berlin.19 The content of these cablesare summaries of private conversations, meetings with foreign government officials, and noteworthyinformation that the outposts send to the capital for discussion behind closed doors; they are notpublic reports. In order to ensure that we are only analyzing private signals, documents classifiedat the “Confidential” level and above, which would not have been disclosed at the time, wereincluded.20 0.7% were unclassified and thus removed.

Records of public signals during the Berlin Crisis come from the Foreign Broadcast InformationService (FBIS). The FBIS was an undertaking originally housed in the Central Intelligence Agencywith the goal of recording and translating foreign countries’ official public statements made throughradio and press agency releases. Particular emphasis was placed on the Soviet Union, for which theFBIS translated over 10,000 releases related to Berlin during the crisis. Images of these originaltranslations are available on-line via NewsBank.

American elites’ evaluations of the Soviet Union’s resolve come from de-classified internal WhiteHouse (WH) documents, collected from both the Dwight D. Eisenhower Presidential Library inAbilene, Kansas and the John F. Kennedy Presidential Library in Boston, Massachusetts. Allarchived collections categorized under “Berlin” were gathered.

Figure 1 shows how these three sets of documents map to our theoretical approach. Also includedin the figure is a node representing hostile events, which speak to Hypothesis 1 and could also bea confounding variable with respect to Hypothesis 3. Since these event data are not new, they aredescribed separately and in greater detail at the end of this section.

Both the State Department and White House documents were individually photographed at theappropriate archives. All the images were then processed using optical character recognition (OCR)software, which converted each image of a document into computer-readable digital text.21 A verysmall scattering of hand-written documents were omitted from this process.22 Digitized versions ofthe FBIS records were included in each document’s metadata and were extracted for this analysis.

It is worth emphasizing that this data likely represents the most comprehensive coverage of the

NYT (Events) WH (Elite Evaluations)

FBIS (Public Signals)

DOS (Private Signals)

Figure 1: Diagram of the dynamics and sources analyzed in this study.

18A listing of all collections used is in the Appendix.19Abbreviated as USBER, Mission Berlin was the State Department’s substitute for an embassy in West Berlin.20“Confidential” is the lowest classification level for government information and documents. The Department of

State defines this as information for which “the unauthorized disclosure of which reasonably could be expected tocause damage to the national security that the original classification authority is able to identify or describe” (UnitedStates Department of State 2005, 2). Two levels exist above this: “Secret” and “Top Secret.”

21Per page, OCR accuracy rates at the character level had a mean of 98.0% and median of 99.6%. At the wordlevel, accuracy rates had a mean of 95.8% and median of 98.3%.

22This is also theoretically motivated. Even in the late 1950’s and early 1960’s, official documents meant forcirculation were always typed.

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Berlin Crisis thus far. Historical biases based on curation of these collections is minimal, andfurther mitigated by gathering every document listed as being related to Berlin at these archives.Moreover, practically all archived documents related to the Berlin Crisis are now de-classified.Although the concern that sensitive documents were never archived is fundamentally untestable,several observations suggest that this is not a serious issue. First, the collections include red insertswhich indicate when entire documents are or were classified. As of today, all of these documents areaccessible. Second, less than 1% of declassified documents featured any form of partial sanitizing atthe paragraph or sentence levels. Third, the documents that are currently available already revealsecrets that would have been incredibly sensitive at the time. This includes memoranda discussingdetailed logistics for an American first strike against the Soviet Union, aimed at initiating a generalwar.23 It is hard to envision documents that could contain more sensitive information.

3.3 Measuring Signals and PerceptionsWe have thus far described the creation of raw diplomatic data. This must be translated intoa quantitative measure that gauges the resolve of the Soviet Union and East Germany/Berlin.We create measures of observed Soviet resolve through their public and private diplomatic signals,captured respectively in the FBIS and in State Department memoranda.24 For these two collections,we seek an indication of whether each memorandum or publicly released message reflects Sovietresolve—that is, willingness to use force to achieve its aims in Berlin. In order to see whetherthese signals had any effect on evaluations of resolve, we would then want to turn to White Housedocuments to see whether policymakers appear to express concerns regarding Soviet intent.

It is worth noting that while American policymakers constantly struggled to appraise Soviet resolveby interpreting diplomatic signals, they had a much clearer understanding of Soviet capabilities,which were more tangible and easier to spy upon and scrutinize. National Intelligence Estimatesfrom 1950 to 1983 attest to the detailed knowledge that the United States had regarding the SovietUnion’s material possessions throughout the Cold War.25 Both during and after the Cold War,intent has always been difficult for intelligence gatherers to estimate (Fitzgerald and Packwood2013).

Given the enormous number of documents involved, coding by hand is prohibitive. We thereforeuse supervised statistical learning models to automate much of the process. This involves manuallycoding a much smaller random sample of the data, and then “training” a statistical model toidentify what features of each observation best explain this manual coding. The model is thenevaluated for how well it makes predictions on additional manually coded data that was not usedto train it in order to ensure that the model is not overfitting the training data—a process calledcross-validation. Conditional on performing sufficiently well, this model is then used to predict thevariable of interest for the remaining documents for which the value of the variable is unknown.

The technical details of this process are explained elsewhere.26 Here, it suffices to say that thethree pools of raw text are converted into quantitative data. To do this, cables/releases are firstsplit into 300-word segments to ensure that long documents are analyzed more properly. The

23Memorandum from Carl Kaysen to General Maxwell Taylor, Military Representative to the President. “StrategicAir Planning and Berlin.” September 5, 1961.

24We obviously cannot create direct measurements of the Soviets’ latent resolve, particularly since we do not haveaccess to declassified Soviet documents. Moreover, latent resolve is not directly relevant to our study.

25Steury (1996) provides many of these estimates.26Friedman et al. (2009) provide a seminal resource.

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text in each segment undergoes standard text pre-processing. These include the removal of stopwords such as “a” and “the,” and the stemming of words into tokens (e.g., converting “talks,”“talked,” and “talking” into “talk”). The number of remaining tokens in each segment is countedand recorded. This finally produces a document-term matrix for each collection of cables, whereeach row represents a 300-word segment, and each column contains how many times a token isused. These token counts are the main variables used to train the models and generated predictedvalues of Soviet resolve for each segment.

Each subset of training documents was coded using specific criteria.27 A State Department doc-ument is classified as conveying a private signal of resolve (willingness to use force) if it describesactions which could plausibly escalate to actual hostilities or statements indicating a willingness torisk escalation. At minimum, this typically involved (1) reports of border or convoy incidents thatlasted a long period of time and/or included temporary detainment of Allied forces, (2) discussionsof plausible rumors regarding border closings, or (3) imprecise concerns about loss of reputation.However, reports of very minor or procedural convoy stops do not qualify. At the other end of thespectrum are (4) more serious border incidents where governments send each other memos citingserious consequences for future issues, (5) discussion of explicit threats made by the Soviet Union,and (6) definite concerns about the outbreak of armed conflict or the loss of Berlin, all of whichclearly surpass this threshold.

An FBIS entry is classified as conveying a public signal of Soviet resolve when it uses proactivelynegative language to characterize the West, though not in relation to any specific event. Termssuch as “suppressors and murderers of freedom” and “warmongers” characterize this threshold.Provocative and accusatory language in reference to actual events, as well as explicitly threateninglanguage, all count as being hostile. For example, an entry from August 2, 1961 warns that “Thosewho raise their arms against us will be destroyed on their own territory.” Entries that vaguelycharacterize the West as obstinate or disinterested in peace do not. These classifications are clearlybased on the specific context of the Berlin Crisis, which permits more precise measurement.

U.S. policymakers’ perceptions of or inferences about Soviet resolve are derived from the WhiteHouse documents. In order for such a document to be coded as reflecting concerns over Sovietresolve, a couple conditions must hold. First, the document must refer to a significant event, orspeak to the private or public circumstances listed for State Department and FBIS entries above.Second, the document itself must express concern that the event or statement indicates a significantSoviet willingness to engage in hostilities. As such, White House memoranda can indicate concernsover the Soviets’ willingness to use force based on any of the three sources of information available(i.e., Soviet actions, private signals, or public statements). For example, the following White Housedocuments show that policymakers in Washington D.C. evaluate Soviet resolve conveyed throughpublic and private channels.

Public Signal: November 1, 1961

In his [Khrushchev’s] July 8 speech, he attributed motives of military pressure againstthe Communist Bloc. In response among other threats, he spoke of a 100 megatonsuper-H bomb which he said had been devised. From other reports as well, we learnthat Khrushchev was especially stung by this speech. On August 7, Khrushchev madea speech in which he stressed the horrendous consequences of a nuclear war, a speech

27The authors and a third party produced two sets of codings. In terms of intercoder reliability, accuracies were0.89 (DOS), 0.91 (FBIS), and 0.85 (WH); F1 scores were 0.93 (DOS), 0.97 (FBIS), and 0.91 (WH). Discrepancieswere resolved via further investigation and discussion, and these revised codings were used in the trained model.

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Collection # Docs # Segments Hand-Coded

State Department (DOS) 3,977 7,777 804FBIS 10,715 13,577 503White House (WH) 3,726 15,499 602

Table 1: Summaries of all three sets of archival data.

in this respect unusual for delivery to a domestic Soviet audience.

Private Signal: August 24, 1961

[In a private conversation,] Khrushchev said that the West was now threatening to cutoff trade and even to go to war if the Soviet government signed a peace treaty. If othercountries strengthened their military forces in Germany, the Soviet Union would do thesame and could always have forces in a position to protect the territory of its ally theGDR. But in any case, modern wars would be fought with nuclear weapons. The SovietUnion and also the USA would no doubt lose tens of millions but the Soviet Unionwould certainly go to war if the Western Allies tried to force their way through to WestBerlin after the Soviet Union had signed a peace treaty with the GDR. It would howeverbe ridiculous for two hundred million people to die over two million Berliners.

Table 1 summarizes all three sets of archival data. The hand-coded segments are processed using apredictive model that finds relationships between the tokens used in a segment and the segment’sclassification. Of the many predictive models available, the balanced random forest model exhibitedthe best overall performance compared to several other alternatives.28

The balanced random forest model is applied to the three full datasets (document-term matrices) tocreate a predicted probability of each segment exhibiting concerns over Soviet resolve. Dependingon the hypothesis tested, we either utilize this raw predicted probability or dichotomize it using acutpoint of 0.5 to create a binary variable.

Through this process, we generate three sets of time series data that reflect the State Department’sperceptions of Soviet resolve from private diplomatic interactions with the Soviet Union regardingBerlin; the general hostility publicly expressed by the Soviet Union regarding the Berlin Crisis; andthe White House elites’ perceptions of the Soviet resolve during the crisis.

To indicate the face validity of this new data, we identify eight key moments of tension or politicalimportance during the Berlin Crisis. These include the following:

(a) 11/10/58: Khrushchev’s First Ultimatum(b) 6/4/61: Vienna Summit; Khrushchev’s Second Ultimatum(c) 8/13/61: Start of Construction of the Berlin Wall(d) 10/22/61: Checkpoint Charlie Standoff(e) 8/17/62: Killing of Peter Fechter at the Berlin Wall29

28Details on this specific method are provided by Breiman (2001) and Chen et al. (2004). Technical results fromour analysis are in the Appendix.

29Fechter was an East German that attempted to flee to West Germany by traversing the Berlin Wall. He was shotby East German guards while standing on the wall, in plain sight of many. His death was one of the first involvingthe barrier. Many historical accounts of Berlin Crisis do not mention this incident, even though the death causedimmense anxiety in West Berlin (as evidenced by the enormous spike in the State Department’s levels of perceivedhostility). This emphasizes the risks involved with retrospectively identifying “important” events.

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(a) (b) (c) (d) (e) (f) (g) (h)

Figure 2: Number of documents predicted to express Soviet resolve in the three document collections, atthe weekly level.

(f) 9/25/62: Berlin Air Corridor Incident(g) 10/10/63: 15-Hour Detainment of U.S. Army Convoys(h) 11/4/63: Autobahn Tailgate Crisis

Figure 2 displays the predicted data and also marks those events. The generated data aptly identifiesthese qualitatively important moments, which increases our general confidence in the data’s overallutility.

3.4 Accounting for ActionsWe account for events from the Berlin Crisis using headlines and abstracts from the New YorkTimes. Between January 1, 1958 and December 31, 1963, the New York Times had 14,178 arti-cles related to Berlin in some way. Of these, 1,601 articles used one of several terms that couldreflect conflict. These include “harass,” “suspend,” “seize,” “ambush,” “raid,” and the like.30 We

30Many of these terms are gleaned from the Conflict and Peace Data Bank, also known as COPDAB (Azar 1982).While COPDAB presents a ready-made data source for hostile activity between superpowers, we opt to create newevent data for several reasons. First, COPDAB was released nearly forty years ago and provides no references of

15

manually coded whether each of these 1,601 article actually reported on a concrete military actionreflecting hostility. Four types of events qualified: shootings of refugees (8 events); detainment ofWestern military personnel, citizens, or press (33 events); detainment or halting of military convoysand transports (89 events); and nuclear or missile tests (7 events). A total of 137 events emergefrom these news articles. Figure 3 illustrates the frequency of these hostile military events at theweekly level.

4 AnalysisWe now proceed to evaluate evidence related to the proposed hypotheses. In doing so, we firstaddress Hypothesis 2 regarding the noisiness of public and private diplomatic signals. We thenturn to Hypotheses 1 and 3, which speak to the absolute and relative impacts of both channels onelites’ evaluations of Soviet resolve.

4.1 Variation Across SignalsFigure 4 shows the overall distributions of signals for public and private messages from the FBISand State Department, respectively. It is clear that the two distributions are not alike, that thedistribution for FBIS documents is especially non-normal, and that a greater proportion of privatesignals tend to be associated with higher levels of perceived hostility.31

The across-signal variances for public and private signals are 0.038 and 0.033, respectively. Toensure that this difference is actually significant, we apply a Fligner-Killeen test for the homogeneityof variances across samples, which is robust to deviations from normality (Conover et al. 1981).The test strongly rejects the null of homogeneous variances (χ2 = 66.958, p� 0.001).32 This resultis consistent with Hypothesis 2: across messages, public statements tend to provide a less focusedoverall signal than private ones.

0

2

4

6

1958 1960 1962 1964

Year

Con

flict

Eve

nts

Figure 3: Hostile military events over the Berlin Crisis.

rhe resources used to create it. Second, and on a related note, COPDAB may be incomplete. In the Appendix, weprovide more information on these issues with COPDAB but also show that most of our main findings are intacteven when using COPDAB.

31A two-sample Kolmogorov-Smirnov test decisively rejects the null; D = 0.20873, p � 0.001.32Other tests, such as the F -test, Barlett’s test, and Levene’s test, are not as appropriate for non-normal data.

Even so, we note that they all strongly reject the null as well, at p � 0.001.

16

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DOS (Private)

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Figure 4: Density plot of predicted probabilities of Soviets’ willingness to use force as reflected in publicand private signals. Higher values represent greater perceived resolve.

4.2 Diplomatic Signals’ Small EffectsHypothesis 1 postulated that, due to the high and arguably overwhelming volumes of informationthat define real-world politics, neither public nor private diplomatic signals should have a largeimpact on policymakers’ evaluations of resolve, especially when compared to the effect of events.Hypothesis 3 went one step further: If Hypothesis 2 was true and public signals were noisier thanprivate ones (and this appears to indeed be the case), then private signals may have relativelystronger effects on perceptions.

These notions are tested using a series of regressions. The primary outcome variable is the numberof White House memoranda classified to convey perceived threat. The unit of analysis is theweek. This level was chosen to allow for dynamic activity while also overcoming some estimationchallenges that arise from the relatively high frequency of zeroes in daily-level data.

The analysis in this study assumes that temporal co-occurrence or proximity of signals indicatesthe processing of diplomatic signals and/or events by elites. That is, if a spike in private signalsof resolve via the State Department is immediately followed by an uptick in concerns over Sovietresolve within the White House, we presume that those private signals helped cause the increase.While we believe this is a reasonable approach and assumption, potential refinements are discussedfurther in the Conclusion.

Initial results are displayed in Tables 2. The first three models investigate the impact of public andprivate diplomatic signals on White House evaluations, while the next three models also includeevents.

Models 1 and 4 use a Poisson regression with four weeks’ worth of lags—the specification whichminimized AIC—for the dependent variable. Private signals appear to have a positive effect re-gardless of whether we account for the occurrence of events. Meanwhile, public signals have a farsmaller effect on White House evaluations when events are omitted from the analysis. This providesevidence in support of Hypothesis 3. In Model 4, NYT event data is included. The effect of publicsignals decreases and is no longer statistically significant, perhaps indicating that public signals andevents are positively correlated.33 The relative magnitudes of the coefficients in Model 4 speaks

33The correlation between the NYT and FBIS data is 0.553. Between NYT and DOS, it is 0.280. Between DOS

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to Hypothesis 1. One individual act of aggression affects White House perceptions approximatelyfive times more than a State Department document relaying Soviet resolve. It is worth noting thateach week, an average of three State Department documents express suggestions of willingness touse force and two events take place. As such, the effect of private signals in an average week issubstantially smaller than the average weekly effect of events.

Since the dependent variable is an overdispersed count variable, it is more appropriate to use anegative binomial model.34 Models 2 and 5 are negative binomial regressions that include one lagof the dependent variable. The general findings of Models 1 and 4 remain broadly intact. Bothprivate and public signals have positive but small effects, with private signals having relativelyhigher effects. The inclusion of events in Model 5 again nullifies the significance of public signals,and the magnitude for the event coefficient is several times larger than that of private signals.

Models 3 and 6 are negative binomial models with an optimal number of lags for the dependentvariable (three, as determined via AIC). Here, the effect of public signals on White House percep-tions loses significance in both models, while private signals maintain their positive effect. Eventscontinue to have a larger effect on shaping White House evaluations relative to both public andprivate diplomatic signals. These results provide further support of Hypotheses 1 and 3.35

and FBIS, it is 0.294.34The mean is 2.97 and variance is 23.45.35Reanalysis using COPDAB event data (see footnote 30) is in the Appendix.

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Dependent variable:

White HousePoisson Negative Binomial Poisson Negative Binomial

(1) (2) (3) (4) (5) (6)

Private (DOS) 0.027∗∗∗ 0.038∗∗ 0.042∗∗ 0.027∗∗∗ 0.032∗ 0.037∗∗

(0.006) (0.017) (0.017) (0.006) (0.017) (0.017)Public (FBIS) 0.011∗∗ 0.026∗ 0.007 −0.001 0.014 −0.002

(0.005) (0.014) (0.014) (0.005) (0.015) (0.016)Events (NYT) 0.136∗∗∗ 0.206∗∗ 0.176∗

(0.031) (0.094) (0.092)Constant −1.240∗∗∗ −1.503∗∗∗ −1.430∗∗∗ −1.283∗∗∗ −1.600∗∗∗ −1.512∗∗∗

(0.251) (0.313) (0.309) (0.251) (0.319) (0.315)

Lagged DV 4 1 3 4 1 3Observations 303 306 304 303 306 304Log-likelihood -650.615 -516.542 -511.238 -641.330 -513.948 -509.228θ 0.846∗∗∗ (0.129) 0.920∗∗∗ (0.145) 0.866∗∗∗ (0.132) 0.941∗∗∗ (0.148)AIC 1,325.231 1,051.085 1,044.477 1,308.659 1,047.896 1,042.457

Note: ∗p < 0.1; ∗∗p < 0.05; ∗∗∗p < 0.01

Table 2: Regression results from Poisson and negative binomial models.

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4.3 The PAR(p)ModelBrandt and Williams (2001) argue that most traditional approaches to studying count data, includ-ing Poisson and negative binomial regressions, do not properly account for systematic dynamics,leading to model misspecification and potential inefficiencies.36 They instead propose a Poisson au-toregressive model, or PAR(p), to properly analyze dynamic count data. Our main results utilizethis technique.

Table 3 shows the results using four PAR(p) models. Models 1, 2, and 3 include three, five, andseven autoregressive terms, respectively, as well as year fixed effects. Although the inclusion ofadditional autoregressive terms does chip away at the effects of events, the main results still hold.Model 4 is a PAR(7) model with no fixed effects, which is the specification that minimizes AICoverall. Across all of these models, private signals have a positive effect on White House evaluations,while public signals do not. Moreover, the relative impact of events is between six and seven timeslarger than signals from the State Department.

Table 4 provides more intuitive versions of the PAR(p) models’ results by determining the short-term and long-term effects of a one-unit increase of a signal on the White House’s evaluations ofSoviet resolve. That is, we can determine the instantaneous and long-run impacts of one additionalState Department (private) or FBIS (public) document expressing hostility on the number of WhiteHouse documents expressing perceived hostility.

Both short- and long-run effects of both diplomatic signals are fairly muted or non-existent. Theeffects of public FBIS signals are so imprecise and small that the estimate is negative. However,private signals do generate changes ranging from a 0.888% to a 2.784% increase from the meannumber of White House documents, which is 2.48. In comparison, hostile events have a markedlylarger effect on the flow of White House documents, deviating from the mean by anywhere between5% and 19%. In an “ideal” setting, one’s prior belief may be that a single threatening documentfrom a private channel should result in approximately one subsequent White House documentconveying this message.37 This notion of efficient signal transferal seems like a tacit assumptionin crisis bargaining scholarship, but the results presented here indicate a higher inefficient processborne out of a more realistic understanding of the vast and cacophonous information environmentin which diplomacy takes place. This even proves true for events.

Overall, these results provide consistent support for Hypothesis 3, which predicts that privatediplomatic signals should have a larger relative impact on elites’ evaluations than public diplomaticsignals. Hypothesis 1, which postulates that both forms of diplomatic signal should have smallereffects than hostile (and non-verbal) events, also finds support. These results provide the firstsystematic evidence of a hierarchy in signals with respect to shaping evaluations of an adverary’sintentions, with non-verbal events on top, private diplomatic signals in the middle, and publicdiplomatic messages on the bottom.

4.4 The Core of the CrisisCrisis scholars may have some objection to the notion of the Berlin Crisis lasting five years. Acrisis, particularly as envisioned in game theory models, may be a more distinct event defined byan initial challenge and then a sequence of interactions to address it (Snyder and Diesing 1977).

36See White (1994) for more details on this matter.37A number greater than 1 would portray a multiplicative effect and growth in concerns.

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Dependent variable:

White House

PAR(p)

(1) (2) (3) (4)

Private (DOS) 0.032∗∗∗ 0.036∗∗∗ 0.036∗∗∗ 0.036∗∗∗

(0.011) (0.011) (0.012) (0.012)Public (FBIS) −0.008 −0.008 −0.012 −0.010

(0.014) (0.016) (0.018) (0.016)Events (NYT) 0.219∗∗∗ 0.173∗ 0.186∗ 0.220∗∗∗

(0.082) (0.090) (0.104) (0.084)Intercept 0.214 0.279 0.244 0.158

(0.246) (0.275) (0.311) (0.198)ρ1 0.178∗∗∗ 0.141∗∗∗ 0.134∗∗∗ 0.142∗∗∗

(0.039) (0.036) (0.036) (0.035)ρ2 0.172∗∗∗ 0.132∗∗∗ 0.125∗∗∗ 0.133∗∗∗

(0.037) (0.035) (0.035) (0.033)ρ3 0.157∗∗∗ 0.122∗∗∗ 0.109∗∗∗ 0.115∗∗∗

(0.035) (0.034) (0.032) (0.032)ρ4 0.061∗∗ 0.046 0.047

(0.030) (0.031) (0.031)ρ5 0.065∗∗ 0.048 0.050

(0.030) (0.030) (0.031)ρ6 0.072∗∗ 0.078∗∗

(0.031) (0.030)ρ7 0.036 0.035

(0.030) (0.030)Year FEs X X X

Observations 304 302 300 300Log-likelihood −518.684 −512.784 −502.917 −503.702AIC 1059.367 1051.568 1035.833 1027.404

Note: ∗p < 0.1; ∗∗p < 0.05; ∗∗∗p < 0.01

Table 3: Results from PAR(p) models.

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PAR(3) PAR(5) PAR(7) PAR(7)with FEs with FEs with FEs w/o FEs

Short-Term DOS 0.034 (1.372%) 0.027 (1.089%) 0.025 (1.009%) 0.022 (0.888%)FBIS −0.008 (-0.323%) −0.006 (-0.242%) −0.008 (−0.323%) −0.006 (-0.242%)NYT 0.228 (9.198%) 0.131 (5.285%) 0.125 (5.043%) 0.132 (5.325%)

Long-Term DOS 0.069 (2.784%) 0.056 (2.259%) 0.057 (2.299%) 0.054 (2.178%)FBIS −0.016 (−0.645%) −0.013 (−0.524%) −0.018 (−0.726%) −0.015 (−0.605%)NYT 0.463 (18.678%) 0.273 (11.013%) 0.289 (11.659%) 0.330 (13.312%)

Table 4: Short-term and long-term effects on the White House variable. In parentheses are the percentagechange in the overall mean.

The information environment in immensely concentrated moments of tension may, in theory, bestarker and set a better stage for public hand-tying. As such, the analysis done thus far may notbe an honest reflection of dynamics during a “crisis” as understood by formal models.

To address this concern, we try examining a subset of the six-year period most strongly associatedwith the Berlin Crisis, which also represents a series of escalatory moves mutually understood byboth sides to be a crucial test of commitments to Berlin: June 4, 1961 to November 9, 1961. Thisfive-month period is book-ended by the calamitous Vienna summit (where Khrushchev made hissecond ultimatum) and a Soviet proposal for a compromise solution on Berlin (Leng 2000).38 Inbetween these two events, the Berlin Wall emerged, and American tanks faced off against Soviettanks at Checkpoint Charlie. We utilize data from between June 1 and November 15, 1961 to makeour assessments.

Figure 5 displays overall distributions of observed resolve across time periods and sources. Table 5shows that levels of perceived hostility indeed become higher during the main crisis in both publicand private channels. Table 6, which includes results for four Fligner-Killeen tests of homogeneityof variances, indicates that public statements feature more noise across signals than private state-ments, both inside and outside of the key crisis; variation in public signals during the crisis is alsohigher than variation in public signals at other times. This latter finding adds further doubt to crisisbargaining scholarship which implies that public signals should be especially forceful during crisesin order to effectively relay credible threats. In any case, Hypothesis 2 appears valid regardless ofwhether we focus only on the peak crisis or not.

This critical crisis period lasts only about 160 days. Currently, this renders intractable regressionsanalogous to those in Tables 2 and 3. Weekly-level analysis of this peak crisis period would bebased on merely 22 or 23 observations, which is not sufficient to produce reliable results.39

Nonetheless, the results provided indicate that, while the intensity of diplomatic signals may indeedbe higher during extraordinary moments of tension, private communications continue to be a moreprecise source of information to understand an adversary’s resolve. This is far from trivial; thetime between June and November 1961 provides an “ideally” critical scenario in which public

38For more details on this proposal, see “Soviet Modifies Berlin Proposal; U.S. Unimpressed” on the front pageof the New York Times on November 10, 1961. While the plan received a tepid response, it signified a more pacificshift in the Soviet Union’s approach to the Berlin problem.

39Daily-level regressions, on the other hand, produce unstable estimates based on minor changes in model speci-fication. This is especially true for the event data, where different specifications for lags drastically affect estimatedcoefficients for all variables. Future efforts will include the collection of improved event data, as well as more researchto understand when and how news of events permeated through bureaucratic documents.

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Period Late 1961 Other

(d) Public signals

Figure 5: Distributions of observed Soviet resolve via diplomatic signals.

Non-Crisis Crisis t-test KS test

DOS 0.389 0.420 p� 0.01 p� 0.001FBIS 0.299 0.382 p� 0.01 p� 0.001

t-test p� 0.001 p� 0.001KS test p� 0.001 p� 0.001

Table 5: Mean levels of observed Soviet resolve, by signal source and time period. Results of t-tests andKolmogorov-Smirnov two-sample tests are presented for each row and column.

23

Non-Crisis Crisis FL test

DOS 0.033 0.034 p = 0.595FBIS 0.036 0.039 p = 0.0006

FL test p� 0.001 p = 0.001

Table 6: Variances in observed Soviet resolve across signals, by signal source and time period. Results ofFligner-Killeen tests are presented for each row and column.

declarations should, in theory, produce the greatest strategic and political traction.

5 ConclusionMore than five decades ago, Thomas Schelling established a remarkably cogent and calculatingframework for understanding the diplomacy of conflict behavior. The notions of credible com-mitment and rationality have left an indelible mark on the study of crisis bargaining, and havecompelled scholars to develop a systematic understanding of seemingly arbitrary behavior. In thelast two decades, audience cost theory has become the primary prism through which scholars debatethe effectiveness of public and private diplomatic signals in influencing perceptions. The predom-inant belief remains that public hand-tying is a costly act that conveys far greater commitmentthan a seemingly costless message relayed behind closed doors.

This logic is undeniably compelling and intuitive. Great strides have been made to clarify thestrategic considerations of a crisis situation, and how different actions provide distinct forms ofinformation. However, these laudable efforts, buoyed by a lack of systematic empirical data, haveabstracted away a thoughtful examination of the actual informational environment in which crisisdiplomacy takes place. The tremendous volume of (often dissonant) information that passes throughthe government, involving a constantly shifting array of priorities, pulls at some of the threads thathold together many contemporary views of crisis bargaining. The additional idea that diplomaticsignals—particularly public ones—are noisy is a natural one, but has been disregarded by rationaltheories of diplomacy.

These are not superfluous details or theoretical window dressing. Many extant works on crisisresolution may have overstated the absolute and relative effects of public and private signals. Byfailing to consider the quantity and quality of information policymakers confront, scholars haveeither argued that only public signals are effective, or that private signals can sometimes also beeffective. Two additional options are inherently omitted: that neither signal has a substantialeffect, and that private signals may be more effective than public ones.

In this paper, we used a combination of archival, statistical learning, and time series methodsto evaluate these claims. The approach was new for crisis bargaining and permitted one of thefirst quantitative analyses of the effect of public and private diplomacy on evaluations of resolve.Critically, we did this using the Berlin Crisis of 1958 to 1963—a period of immense danger involvinga clear focal point and the possibility of nuclear war. The Berlin Crisis should be a “crown jewel”of crisis bargaining that provides an ideal set of conditions for public and private communicationsto shape American elites’ perceptions of the Soviet Union’s intentions.40 Even in this best case

40Indeed, concerns of the Cold War escalating to nuclear hostilities motivated the work of Schelling and hiscontemporaries.

24

scenario, we find that neither form of diplomatic signal has a substantial effect on the WhiteHouse, that public signals are noisier than private ones, and that private signals are generally moreefficacious in altering perceptions.

We emphasize that these findings do not suggest that public signals are universally less effective. Asmany anecdotes in audience cost literature point out, there are clear instances in which categoricallyhostile threats made out in the open should hold greater weight than an analogous threat madein secret. Nonetheless, such instances are rare and must be undeniably clear to be understood inthe moment. Our contention, backed by new data, is that such crystal-clear scenarios are not thenorm.

As stated in Section 4, our analysis assumes that if a State Department memo, FBIS report, ormajor event that expresses Soviet resolve is quickly followed by an analogous jump in the WhiteHouse, then the original signal helped influence the White House’s beliefs. In the future, it may beinformative to re-examine the White House documents that express concerns over Soviet resolvein order to ascertain what motivated them—an event, a public diplomatic signal, or a privatediplomatic signal. Indeed, one could attempt to cross-reference all the documents to figure out whatspecific signals were moving from one place to another. This would be a substantial undertaking,and perhaps the basis of a separate paper that examines what specific kinds of signals work up thebureaucratic ladder and how they are manipulated/augmented along the way.

With that said, we still feel that our supposition is a relatively sound one, and that our results arequite meaningful as they stand. An important argument in this paper is that real-life bureaucraticactivity is frenetic and overwhelming in terms of information. Given the pace and volume at whichgovernmental activity takes place, institutional memory is short and is not always driven by a smallor easily identifiable set of signals. Concerns about Soviet resolve did not only spike in responseto “smoking gun” events, but constantly and uneasily fluctuated based on everyday diplomaticactivity.

This study, the new text-based data, and the general framework we have outlined set a foundationfor further research on several important aspects of diplomacy. We mention two here.

Very little work has been done to systematically understand the strategic use of private and publicsignals in diplomatic interactions and crisis bargaining, except to say that public signals may bemore credible. By seriously considering the temporal sequencing of these two forms of signals aswell as provocative events, we could illuminate the manner in which elites send and manipulateinformation. For example, if private signals tend to be followed by a growth in public signals, thisindicates a dynamic of escalation where private communication failed to stem an issue, pushingthe disagreement into the public spotlight. Such a dynamic would be largely consistent with theimplications of costly signaling literature. Conversely, if public signals are followed by privatesignals, this suggests that elites use private communications to highlight which public messages areimportant and to be taken seriously. It is also possible that no temporal relationship exists, inwhich case public and private messages relay fundamentally different information and do not serveto filter or amplify some specific message. Any of these three scenarios would be revealing andencourage scholars to more seriously consider the calculus of diplomatic communications.

A key contention in this paper is that elites are literally incapable of processing and acting uponevery single piece of information running across their proverbial desks. Policymakers must choosehow to allocate their time and attention to an enormous array of issues and potential problems.Our study provides evidence that the consequence of an information-overloaded environment—attenuated levels of information/signal processing—indeed exist, but does not directly speak to

25

when and why actors shift their focus to a specific topic of concern, or what effects this has onbeliefs and policymaking.41 Future studies could adopt a document-based approach to study thisdynamic. By collecting a wider array of archived governmental documents from entire entities(such as the National Security Council or Department of State), scholars could speak directly tothe causes and effects of information processing and agenda-setting on foreign policy.

Tensions concerning North Korea, the South China Sea, and Syria, among other locales, continueto make crisis diplomacy relevant today. On one hand, our findings are discouraging for the studyof contemporary conflicts, since we cannot properly observe private diplomatic signals in the midstof current affairs. On the other hand, the results also suggest that we should temper our reactionsto various provocative statements that parties make in public. Regardless of the implications toscholars’ abilities to study current-day issues, or to predominant theories of diplomacy, our theo-retical understanding of information and empirical contribution of document-based data establisha more rigorous and pragmatic approach to learning when, why, and how crises unfold.

41Jones and Baumgartner (2005) and Yarhi-Milo (2014) speak broadly to this concern.

26

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AppendixSupplementary information on the data, predictive models, and main statistical results are providedbelow.

Document SourcesDwight D. Eisenhower Presidential Library - Abilene, KS

Collection Series Box(es)Papers as President National Security Council 5, 7, 10-13

(Ann Whitman File) Diary 37-45, 49, 51Administration 7ACW Diary 10-11Cabinet 14Dulles-Herter 9-12International 15-16, 24-25, 44, 50, 51-

52International Meetings 4

Eleanor L. Dulles [Germany and Berlin, 1957-1959] 13, 31, 36John F. Dulles Chronological 17

Gerard C. Smith 1-3Christian Herter [Chronological File, 1958-1959] 6-7

[US Policy Toward Germany] 8Lauris Norstad [Germany and Berlin, 1956-1962] 24, 48-49, 61, 64, 72, 86,

88, 97, 103, 105,112-113

White House Office, NSC Executive Secretary’s Subject File 7-11White House Office, International 5-6

Office of the Staff Secretary Subject, State Department Sub-series

3-4

John F. Kennedy Presidential Library - Boston, MA

Collection Series BoxesNational Security Files The Berlin Problem 81-98

National Security Action 11, 36, 41, 58-59, 62, 70,Memoranda 78, 82, 93, 109, 116, 128,

158, 328-342

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National Archives II - College Park, MD

Collection Series BoxesDepartment of State Records Central Files (RG 59) 1887-1889, 1902-1910,

3531-3535, January-December 1963

Example PredictionsBelow, we present several segments from our data. Their dates, predicted probabilities of signalconveying resolve (for DOS cables and FBIS) and predicted probability that policymakers perceivedor made an inference about Soviet resolve (for White House documents) based on the balancedrandom forest model are provided.

Eisenhower and Kennedy Presidential LibrariesJanuary 29, 1959Predicted probability: 0.603

...mobilize world opinion against the Soviet Union as a violator of agreements, a user offorce and a threat to the peace. The situation could be taken to the Security Counciland, in the event of veto there, to a special session of the General Assembly; b) Militarypreparations would be intensified and at this point could include measures which wouldbe observable, as, for example, the evacuation of dependents from West Berlin, andpossibly from Germany. 5. The decision to use additional force would be subject togovernmental decision in the event that the double barreled effort mentioned abovewas not successful. (Consideration would be given to the possibility of the stationing ofWestern allied inspectors in lieu of the withdrawn Soviet inspectors at the check points.)6. Concurrently with the development of the foregoing program an effort would be madeto bring about around the middle of April a foreign Ministers ’ meeting with the SovietUnion on the various aspects of the German question. These talks might provide acover which would facilitate the indefinite postponement or modification by the SovietUnion of their present ultimatum as regards Berlin. (It is assumed that allied agreementwould be obtainable along these lines. If not the question of U.S. action would have tobe considered in the light of the allied position.)

June 30, 1961Predicted probability: 0.749

... This is necessary to derive from all preparations a full and effective deterrent affectby convincing the Soviets of US determination and commitment to use whatever degreeof force may be required to react successfully to any attempt at interference with accessto West Berlin. 2. The specific measures, some of which have been previously listed,which should be taken are as follows: a. Place SAC in an increased state of readi-ness which could be maintained over a prolonged period of crisis without degrading itsstrategic capability. b. Intensify civil defense measures including the construction offallout shelters and the placing of substantial contracts for the manufacture of radiationdetection meters. c. Place all US forces world-wide in an increased state of readiness.

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d. Discontinue the inactivation and/or retirement of operational forces, such as B-47wings and amphibious ships. e. Resume nuclear testing. f. Resume U-2 flights andreconnaissance flights over Siberia and the Soviet Arctic. g. Step up the ICBM programand the program for “hardening” missile sites. h. Accelerate current action to improvecommand and control capabilities to include placing the Joint Action Control Staff ina completely operational status. i. Increase air defense measures. [TOP SECRETTOP SECRET 19 THE USE OF FORCE AFTER ALLIED ACCESS TO BERLIN ISBLOCKED] 1. While it is correctly recognized in the Acheson Report of 27 June 1961...

October 6, 1961Predicted probability: 0.938

...access engaging ground origins of any interference. Extend size and scope as necessaryC. Maritime control naval blockade or other world-wide measures, both for reprisal andto add to general pressure on Soviets. Use nuclear weapons starting with one of thefollowing courses of action for continuing through C below if necessary: A. Selective nu-clear attacks for the primary purpose of demonstrating the will to use nuclear weapons.B. Selective nuclear attacks to achieve in addition significant tactical advantage suchas preservation of the integrity of Allied forces committed or to extend pressure towardthe objective. Comment B. Opposing strengths probably will be roughly comparable.Military success locally not Impossible. As political operation, this shows Soviets vis-ibly higher risks of nuclear war. Pace and volatility of extended air action raises risksof rapid escalation. C. Lacking direct relation to Berlin, may lock influence on accessdecisions and entail political liabilities. Exploits pronounced Allied naval superiority.Delayed impact on nuclear risks. Allies only partially control the timing and scale ofnuclear weapons use. Such use might be initiated by the Soviets, at any time after theopening of small-scale hostilities. Allied initiation of limited nuclear action may elicit areply in kind; it may also prompt unrestrained pre-emptive attack. C. General nuclearwar...

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July 15, 1963Predicted probability: 0.174

...explanation of the press leaks which exposed the confidential deliberations to thepublic. See Embtel 134 July 11. 8. IAEA AGREEMENT ON PRIVILEGES ANDIMMUNITIES It was agreed to discuss on July 15 the Allied reply to the Czech andHungarian statements on the application to Berlin of the IAEA Agreement on Priv-ileges and Immunities. 9. LEOPOLD-BEKRENDT TALKS Dr. Oncken stated thatLeopold and Behrendt met in Berlin on July 8. He informed the Group that the meetingwas routine and that there were no political matters discussed between them. CountdAumale asked if the settlement of the swing accounts was discussed. Dr. Onckenreplied that the swing was settled on June 30 and that the accounts were almost inperfect balance. 10. SIEMENS FIRM EXPORTS TO BULGARIA Dr. Oncken statedthat the Siemens firm in West Berlin informed the Foreign Office that the BulgarianAmbassador to the Soviet Zone had asked the firm if he could visit the Siemens of-fice in West Berlin to inspect some goods which are to be exported to Bulgaria withinterms of the German-Bulgarian trade agreement. The Foreign Office asked Siemensnot to receive the Bulgarian Ambassador but to inform him that the Bulgarian trademission in Frankfurt/Main would be the appropriate office to inspect the goods. 11.LIETZENBURGERSTRASSE PROPERTY IN BERLIN Dr. Oncken raised the matterof the application by the Soviet Embassy in East Berlin for permission to undertakeadditional construction work at the Soviet property at Lietzenburgerstrasse II in WestBerlin. He stated that the Foreign Office has now been informed that the British Com-mandant has told the Charlottenburg authorities to inform the Soviet Embassy in EastBerlin that the first application was not correctly submitted and that a new applicationshould be...

November 16, 1963Predicted probability: 0.350

ANNEX II The numbers which appear in parentheses after the various elements ofthe proposals in this Annex represent a rough attempt to quantify on an ascendingscale of 1 to 10, the relative importance of each of these elements. secret annex IIA. Proposals for Negotiations Draft Principles Paper of June 12, 1962. Advantages toWest 1. Berlin : a. Facilitation of transportation of people and goods and regulationof public utilities and sewage between the two sectors of Berlin would be in interestof the West. (5) b. Communication between East Berlin and West Germany to beadministered by International Access Authority. (8) c. Quadripartite Committee ofDeputy Foreign Ministers to see to it that West Berlin should be free to choose itsown way of life its social order respected its viability and prosperity maintained andits unrestricted communication with West Germany assured. (6) Advantages to East1. Berlin : Establishment by East and West Berlin of all-Berlin technical commissionto facilitate transportation of people and goods and regulation of public utilities andsewage between the two sectors. (4) 2. Germany: a. Establishment of two mixedtechnical commissions in East and West Germany to promote economic exchanges andpromote free cultural and technical contacts. (5) b. West would respect arrangementsmade with East Germany (8) d. Vital interests of each of the quadripartite powers inBerlin to be protected (4)...

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State Department CablesSeptember 12, 1962Predicted probability: 0.895

1 Adopt their position for sake of uniformity: 2 Maintain our own proposed position infull: or 3 Adopt in-between position. There are advantages to uniformity since if, by rarechance, APC’s forced entry into both us and another sector disparate responses mightgive impression of weakness greater than would be case if we both took not entirelyunreasonable step of escorting them in and out. Much would depend however on modeof entry. If an APC came relatively unchallenged through crossing point which wasmanned only by West Berlin police allied escort would not seem unreasonable the firsttime. If an APC forced its way through allied roadblock however conceivably injuringpersonnel in process, vigorous response obviously called for and considerations of alliedunity would not be controlling.

April 12, 1962Predicted probability: 0.515

FROM: Paris, TO: Secretary of State, SECRET Recd : April 12 1962, 11:30 p.m.Summary NAC discussion focused on measures against surprise attack and NATO-Warsaw non-aggression pact or declaration. Reformer only substantive comment madeby Belgium, which called attention to difference between us, presented emphasis on fixedground inspection as contained in US position paper circulated today and 1957 view thataerial inspection supported by mobile ground inspection were more important elementsguarding against surprise attack. Consensus of opinion, however, favored postponementof further discussion.

36

December 5, 1960Predicted probability: 0.206

4. Soviet Overflights Over the Federal Republic: The British representative referred tohis Embassy’s Note Verbale of November 9 asking that the German Air Traffic Con-trol Center in Hannover turn down any Soviet overflight requests made directly to ituntil the joint approval of the three Embassies had been obtained. He stated that theBritish Civil Air Attache had been led to believe, from talks with some German col-leagues, that the Foreign Office now intended to answer this note by suggesting thatthe German traffic authorities, in such cases, merely themselves route the Soviet flightsoutside Federal Republic Air Space. Dr. Northe did not comment on this observation.5. Countermeasures: The British and U.S. representatives expressed disappointmentthat Dr. Northe had not seen his way clear at the last meeting, or at the current one,to inform the three Embassies of any details of the government’s plans or thinking con-cerning resumption of IZT. Mr. Tyler remarked that the end of the current agreementwas now only a month away, and the Embassies had still not been consulted in detailon the subject.

Foreign Broadcast Information ServiceJuly 19, 1958Predicted probability: 0.728

GDR Delegates’ Statement

Berlin, ADN, in German Hellschreiber to East Germany, July 19, 1958, 0757 GMT–L

(Text) Stockholm–The German Peace Council and the GDR delegation issued a state-ment on July 18 on the American-British aggression in the Near East. It sharplycondemns the imperialist invasion, especially the aid extended by the West GermanAdenauer government. These events unmasked the true character of NATO and showedwhat it meant to be an ally of aggressors. Overnight West Germany was cooperatingin an attack. The statement asks what is to become of West Germany if she remainedthe assembly point and springboard for wars of aggression.

The delegation called on the citizens of the GDR to demand the immediate cessation ofthe assistance extended by Bonn to the aggressors and the immediate withdrawal of theinterventionist troops from the Lebanon and Jordan. This also implied the immediateliquidation of U.S. military bases in the Federal Republic. The situation was revealingonce more which of the two German states was a state of peace.

The statement was signed by the head of the delegation and president of the GermanPeace Council and by leading members of the Peace Council.

37

March 17, 1959Predicted probability: 0.880

U.S. People’s Will Disregarded

Moscow, Soviet North American Service in English, Mar. 17, 1959, 0310 GMT–L

(Nikolai Andreyev commentary)

(Text) Statements by responsible officials of the Pentagon at the sittings of the Senatepreparedness subcommittee were made public the other day. These statements cannotbut cause grave concern. It is not because of the horrors that the Pentagon leadersthreaten are in store for the USSR that I want to call your attention to those statements.It is because the political and military course outlined by these generals is fraught withimminent danger for all peoples, Soviet and U.S. alike, and for all mankind.

What does the U.S. military advocate? The keynote of the utterances of General TaylorChief of Staff of the Army and of General White Chief of Staff of the Air Force istotal nuclear war over Berlin. Just imagine: total nuclear war. Not long ago, WalterLippmann remarked in the New York HERALD TRIBUNE that the intention to resortof force merely to prevent the East Germans from checking papers of the Ailied personnelon the road to West Berlin could start a war on an idiotic issue. It seems to me thatsome Pentagon leaders want to start a nuclear war on this idiotic issue.

One could laugh at the bravado of those gentlemen if it were not for the fact that theyare high-ranking commanders speaking at official hearings in Congress and not to theiryoungsters at the dinner table. The public is allowed to read only the censored versionof the Senate hearings, but even so one finds enough to question the mental soundness ofthose who made these statements. General White. for instance. in his global strategicdeliberations. doomed whole nations of Europe offhand. dismissing the very real dangerof...

October 7, 1959Predicted probability: 0.071

GUINEA DELEGATION–A Guinea Government delegation arrived at Berlin Schoene-feld airport Oct. 7 to attend the GDR anniversary celebrations. The delegation consist-ing of Fode Papaou Toure, president of the Guinea Court of Appeal, Ahmascu Thiam,National Assembly deputy, and Camara, Rational Assembly deputy and general secre-tary of the foreign trade office, was welcomed at the airport by Sepp Schwab, deputyminister for foreign affairs, Carl Eckloff, deputy minister of foreign and intra-Germantrade, and Manfred Flegel, member of the Presidium of the National Council of theNational Front. A guard of honor of the National People’s Army was drawn up at theairport. (Berlin, ADN, German, Oct. 7, 1959, 2004 GMT–L)

38

May 5, 1960Predicted probability: 0.404

KHRUSHCHEV SPEECH EXPOSES US POLICY

Berlin, Deutschlandsender in German to East and Wsst Germany, May 5, 1960, 2307GMT–L

(Albert Reiss commentary on Khrushchev Supreme Soviet Speech)

(Excerpts) I should like to challenge everyone to give the name of a single capitalistcountry where the premier submits such proposals to parliament. Is there a singlecapitalist country which is contemplating removing the burden of taxation from theshoulders of the workers or exempting the small Industrial producers from the pressureof taxes? Certainly not. Taxes are the panacea of the finance ministers in the capitalistcountries. Whenever a hole arises in the state budget it is plugged by taxes, primarilyfrom the packets of the little men. The human tragedies caused by this are not consid-ered important. In the Soviet Union and in all other socialist countries, the aim Is thewelfare of the workers.

If people can breathe more freely today than they could 8, 9, or 10 years ago, this is dueto the initiatives of the Soviet Union. The path to an understanding and coexistenceis, however, obviously not an easy one. We experience relapses into the cold war onthe part of the Western powers. Today, 11 days before the summit conference in Paris,Khrushchev had to comment once more on a series of extremely grave manifestationsbecause they are calculated to place in jeopardy an understanding and the success cf thesummit conference. We learned from Khrushchev today that U.S. aircraft have flownover the Soviet Union twice very recently, the first time on Apr. 9 and the second timeon May 1. The aircraft which violated the frontier of the Soviet Union on May 1 wasshot down. Apart from these open provocations on the eve of the summit conference,which is to...

April 20, 1963Predicted probability: 0.568

GREEN FLIGHT ACCENTS AIR CONTROL NEEDS

East Berlin ADM in German to East Germany 1244 GMT 20 April 1963–L

(Text) Berlin–“Those political circles which by provocation are endangering traffic toand from West Berlin and thereby want to create tension must be aware that they willhave to bear full responsibility for all consequences arising from such disruptive actions,”writes AUSSENPOLITISCHE KORRESPONDEZ, published by the press departmentof the GDR Foreign Ministry, By proper (ordnungsgemaesse) transit arrangements, aneffective stand could be made against the forces interested in a disturbance of peacefulWest Berlin traffic. “Arrangements on this transit traffic, based on international law,are indispensable since this traffic is now taking place, for all practical purposes, withoutlegal basis,” says the article referring to air traffic to and from West Berlin which fliesover GDR territory.

“If, as was the case in the very recent past, U.S. aircraft were to carry out circuitflights to West Berlin, and if a British private aircraft arbitrarily were to use GDR air

39

corridors for a flight to West Berlin, such acts could only be regarded as an attempt tocompromise (belasten) the recently resumed Soviet-U.S. talks about a peaceful solutionof the West Berlin question. Every Western provocation in GDR air corridors onlyproves once again how urgent it is to create proper arrangements about the traffic toWest Berlin.”

AUSSENPOLITISCHE KORRESPONDEZ points out that the latest provocations areeven in contradiction to those (former?) arrangements of the early postwar years, whichthe Western powers would like to invoke. Thus, a document, drafted in 1946 by theair force directorate of the former Allied Control Council, expressly forebade “recklessflights.”

Random Forest Classification ResultsTable 7 provides an array of metrics through which the balanced random forest model used togenerate the predicted data can be evaluated. Figure 6 shows distributions of predicted probabilitiesfor all documents.

Metric DOS FBIS WH

F1 0.864 0.889 0.826F2 0.840 0.889 0.795Kappa 0.490 0.355 0.553Accuracy 0.800 0.816 0.787Sensitivity 0.825 0.876 0.776Specificity 0.717 0.500 0.808AUC 0.858 0.779 0.859

Table 7: Summary of metrics for the balanced random forest model.

40

0

100

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Cou

nt

(a) Department of State

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nt

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Cou

nt

(c) White House

Figure 6: Predicted values.

As stated in the text, an infinitesimal jackknife bootstrap (Wager et al. 2014) is used to generateconfidence intervals for random forest predictions. Figure 7 displays these for the three sets of data.

41

0.000

0.025

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var.h

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Figure 7: Predicted values and associated variances.

Alternate Event Data (COPDAB)As mentioned in footnote 30 of the main text, the Conflict and Peace Data Bank, known collo-quially as COPDAB (Azar 1982), is an extant resource that contains information on internationalinteractions between 1948 and 1978. Many of these include events in and around Berlin.

Events in COPDAB are scored on a 1−15 scale, where 1 represents “voluntary unification into onenation” and 15 represents “extensive war acts causing deaths, dislocation or high strategic costs.”For this study, we look at events that indicate “strong verbal expressions displaying hostility ininteraction” (10 on the COPDAB scale) or higher in which the Soviet Union takes action regardingBerlin/Germany, or in which the East Germans take actions against West Germany or the UnitedStates. 610 events fit these criteria, and are shown on Figure 8. Although COPDAB also hasweighted measures for each event category, they lack inherent meaning and make interpretationof any results troublesome. We therefore use raw counts of events per week as the event variable.Figure 9 compares the COPDAB events with the NYT data used in the main text.

There are several potential issues with the COPDAB data, which motivated the collection andcreation of new event data based on the New York Times.

First, COPDAB is four decades old and probably merits some review. Second, COPDAB does notsource its data and descriptions of each event are not always self-explanatory, so it is not possible toreevaluate the events. Third, because events have very short descriptions and COPDAB attemptsto record incidents for 135 countries, but it is not immediately clear how to identify which events

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Strong Verbal

Diplomatic−Economic

Political−Military

Small Scale Military

Limited War

1958 1959 1960 1961 1962 1963 1964Year

Eve

nt T

ype

Figure 8: COPDAB event types over the Berlin Crisis.

0

5

10

1958 1960 1962 1964

Year

Eve

nts Source

COPDAB

NYT

Figure 9: Comparison of COPDAB and NYT event data.

are related to Berlin versus other interactions between the Western Powers in West Berlin and theSoviet Union in East Berlin.42 Fourth, for the purposes of our study, the “strong verbal expressionsdisplaying hostility in interaction” category is troublesome, as actual COPDAB events with thislabel tend to blur the line between verbal statements and material actions. We want the eventvariable to capture only material events, since FBIS is meant to represent public verbal statements.

Lastly, COPDAB may be missing some important events. A noteworthy example is the 15-hourdetainment of two U.S. Army convoys on October 10, 1963. As noted by the Washington Post onOctober 11, this act was “regarded as the most serious challenge to Western access rights sincethe Communists build the Berlin Wall.” This event is also reported in the New York Times, butCOPDAB has no record of this incident.

All that said, Table 8 replicates the findings in Table 2 of the main paper, using COPDAB. Tables 9and 10 do the same, paralleling results from Tables 3 and 4 of the main text. The main findings areeffectively unchanged in the Poisson and negative binomial models. However, the effect of eventsbecomes substantially attenuated and loses significance in most of the PAR(p) models.

42We look at the subset of events where the Soviet Union acts against the United States, and the event descriptionincludes the term(s) “Berlin,” “Germany,” or “reunification.”

43

Table 8: Results from negative binomial and Poisson regressions, using COPDAB data.

Dependent variable:

White House

Poisson Negative Binomial

(1) (2) (3)

Private (DOS) 0.026∗∗∗ 0.035∗∗ 0.039∗∗

(0.006) (0.017) (0.017)Public (FBIS) 0.010∗∗ 0.025∗ 0.005

(0.005) (0.013) (0.014)Events (COPDAB) 0.079∗∗∗ 0.113∗∗∗ 0.112∗∗∗

(0.016) (0.038) (0.037)Constant −1.327∗∗∗ −1.578∗∗∗ −1.500∗∗∗

(0.251) (0.307) (0.304)Lagged DV 4 1 3Year FEs X X X

Observations 303 306 304Log-likelihood -639.476 -512.517 -506.999θ 0.914∗∗∗ 1.000∗∗∗

AIC 1,304.953 1,045.033 1,037.997

Note: ∗p < 0.1; ∗∗p < 0.05; ∗∗∗p < 0.01

44

Dependent variable:

White House

PAR(p)

(1) (2) (3) (4)

Private (DOS) 0.039∗∗∗ 0.041∗∗∗ 0.042∗∗∗ 0.042∗∗∗

(0.010) (0.010) (0.011) (0.011)Public (FBIS) 0.006 0.004 0.002 0.006

(0.012) (0.010) (0.015) (0.017)Events (COPDAB) 0.008∗∗ 0.061 0.069 0.066

(0.034) (0.038) (0.044) (0.045)Intercept 0.351∗ 0.418∗ 0.425∗ 0.158

(0.200) (0.218) (0.234) (0.211)ρ1 0.169∗∗∗ 0.138∗∗∗ 0.131∗∗∗ 0.149∗∗∗

(0.038) (0.036) (0.035) (0.037)ρ2 0.165∗∗∗ 0.130∗∗∗ 0.123∗∗∗ 0.139∗∗∗

(0.037) (0.035) (0.034) (0.036)ρ3 0.154∗∗∗ 0.121∗∗∗ 0.109∗∗∗ 0.121∗∗∗

(0.035) (0.034) (0.033) (0.034)ρ4 0.057∗ 0.043 0.041

(0.030) (0.031) (0.033)ρ5 0.064∗∗ 0.047 0.046

(0.030) (0.031) (0.033)ρ6 0.068∗∗ 0.078∗∗

(0.031) (0.032)ρ7 0.032 0.030

(0.030) (0.032)Year FEs X X X

Observations 304 302 300 300Log-likelihood −519.778 −513.486 −503.850 −506.537AIC 1061.556 1052.973 1037.701 1033.074

Note: ∗p < 0.1; ∗∗p < 0.05; ∗∗∗p < 0.01

Table 9: Results from PAR(p) models, using COPDAB data.

45

PAR(3) PAR(5) PAR(5) PAR(7)with FEs with FEs with FEs w/o FEs

Short-Term DOS 0.009 (0.363%) 0.009 (0.363%) 0.008 (0.323%) 0.022 (0.888%)FBIS 0.001 (0.040%) 0.001 (0.040%) 0.000 (0.016%) 0.003 (0.121%)COPDAB 0.020 (0.806%) 0.014 (0.565%) 0.011 (0.444%) 0.034 (1.372%)

Long-Term DOS 0.018 (0.726%) 0.019 (0.766%) 0.017 (0.686%) 0.055 (2.219%)FBIS 0.003 (0.121%) 0.002 (0.081%) 0.001 (0.040%) 0.008 (0.323%)COPDAB 0.038 (1.533%) 0.029 (1.170%) 0.025 (1.009%) 0.087 (3.510%)

Table 10: Short-term and long-term effects on the White House variable. In parentheses are the percentagechange in the overall mean.

46