Comments on Trachtenberg

November/December 2006 · Historically Speaking 17 Comments on Trachtenberg RobertJervis Like Halévy, Marc Trachtenberg packs a great deal into a short space. There is a little to disagree with, but much to ponder, probe, and query. As a great admirer of both Trachtenberg and the field of diplomatic history, I strongly agree that it is hard to imagine international theory and international history thriving without each other. This is not to say that they will or should converge, let alone merge. Neither should there be a hardand -fast-division of labor, especially one where historians study particular cases and political scientists draw generalizations and develop theories . Rather, while engaging in close dialogue, they make somewhat different scholarly tradeoffs and embody somewhat different sensibilities . But, at least for the mainstream of both disciplines, the central task is to explain how international politics works. Halévy's statement and Trachtenberg's discussion of it bring up several points, some of them common concerns of historians and international relations (IR) scholars and some that point to a number of the differences. To start with, it is interesting that while Trachtenberg expresses skepticism about the deterministic and static quality of Halévy's argument, the two share a perspective that illuminates current issues of interest to both historians and IR scholars. This is a focus on how much the contemporary actors know about the international scene, what theories (usually implicit) they hold about international politics, and how we explain their beliefs. Furthermore, and this has received increased attention from political scientists recendy , it is not only later scholars who are doing this, but also contemporary actors. That is, we theorize about actors who themselves are theorizing. Most generally, both Trachtenberg and the quotation from Halévy imply that the beliefs and calculations of leaders matter a great deal. This may seem obvious, but in fact denies alternative arguments, common in both history and IR, that people are moved by forces beyond dieir control and indeed beyond their comprehension. In this view the diplomacy of 1914, and indeed of the decade preceding the war, was epiphenomenal, and the real causes lay deeperwithin the states and/or the international system . Although I do not want to address this fundamental question here, I raise it because it is the perspective that informs the entirety of Halévy's essay, which focuses on collective feelings and collective forces and characterizes speculation about how different behavior in the crisis might have prevented the war as "Pills to cure an earthquake!" This issue is perhaps unresolvable, and so it is fortunate that Halévy's wording suggests other interesting questions: "everyone knew, who chose to know ... it was likewise common knowledge . . . everyone knew, JfAo wished to know . . . ." If we can see it, why didn't diey? And if diey could understand the likely consequences of their behavior, and if the outcome was to prove unfortunate, why didn't they behave differendy? Woodrow Wilson making speech at Arlington National Cemetery, May 30, 1915. Library of Congress, Printsand Photographs Division [reproduction number, LC-USZ62-85701]. Let me start with the phrase "common knowledge ." It has entered IR scholarship through game theory. There it means not only that both sides (assuming only two for the sake of convenience) know the same thing, but that each knows that the other knows it, and knows that the other knows that it knows it. (Saying that knowledge is common is not saying that it is correct—all the actors in 1914 "knew" that the war would be short, and knew that odiers knew it.) In this view, although the actors are not omniscient, they generally see quite clearly, and generally see how others see the world. This permits scholars who share this perspective to make very powerful and penetrating arguments. We can build our analysis on the assumption that statesmen could foresee, if not the specific outcomes, then at least the outlines of the others' motives and likely responses . More historically-minded IR scholars, even those like myself who are great believers in the central insights of game theory, object that this assumption simply is not realistic. In case after case that we look at...