The Credibility of Power: Assessing Threats during the "Appeasement" Crises of the 1930s

In 1933 Adolph Hitler became chancellor of Germany and immediately began breaking his country's international agreements. From 1933 to 1938 Germany violated its treaty commitments by rearming, remilitarizing the Rhineland, and seizing Austria.¹ Although Britain and France complained after each German violation, they refused to respond with force. In September 1938 Hitler threatened to invade Czechoslovakia unless Germany was given a piece of Czech territory called the Sudetenland. Once again, the British and French acquiesced to German demands; at the infamous Munich conference, they agreed to pressure Czechoslovakia into surrendering the Sudetenland to Germany. Finally, in 1939, as Germany was preparing to invade Poland, Britain and France took a firm stand. They warned Hitler that if he attacked Poland, they would declare war on Germany. By this time, however, Hitler no longer believed their threats. As the German leader told a group of assembled generals, "Our enemies are worms. I saw them in Munich."²

The lessons of Munich have been enshrined in international relations theory and in U.S. foreign policy. For deterrence theorists, the history of the 1930s shows that countries must keep their commitments or they will lose credibility.³ U.S. leaders have internalized this lesson; the most costly and dangerous moves undertaken by the United States during the Cold War were motivated by a desire to preserve credibility. Concerns about credibility led the United States to fight both in Korea⁴ and in Vietnam⁵ ; during the 1962 Cuban missile crisis, President John F. Kennedy risked nuclear war rather than back down and risk damaging U.S. credibility.⁶ And even after the end of the Cold War, the fear of breaking commitments continues to be a powerful force in U.S. foreign policy.⁷

The notion that a country's credibility depends on its history of keeping its commitments is widely accepted, but is it true?⁸ Does credibility depend on a history of resoluteness? More broadly, what causes credibility in international politics? To answer these questions, this article tests two competing theories of credibility. The first, which I call the "past actions" theory, holds that credibility depends on one's record for keeping or breaking commitments. I test this theory against the "current calculus" theory, which argues that decisionmakers evaluate the credibility of an adversary's threats by assessing (1) the balance of power and (2) the interests at stake in a given crisis.⁹ If an adversary issues a threat that it has the power to carry out, and an interest in doing so, the threat will be believed, even if that country has bluffed in the past. But if it makes a threat that it lacks the power to carry out, or has no interest in doing so, the credibility of that threat will be viewed with great skepticism.

To test the past actions and current calculus theories, this article uses evidence from German decisionmaking during three crises from the 1930s: the Austrian crisis, the Sudetenland crisis, and the crisis over Poland. These cases offer easy tests for the past actions theory. Nevertheless the current calculus theory performs significantly better. Although the British and French backed down repeatedly in the 1930s, there is little evidence to support the argument that their concessions reduced their credibility in German eyes. The credibility of Britain and France did fluctuate from one crisis to the next, but these fluctuations are better explained by the current calculus theory. Furthermore, German discussions about the credibility of their adversaries emphasized the balance of power, not their history of keeping or breaking commitments.¹⁰

The past actions theory is intuitively appealing because it accurately describes how people assess credibility in their everyday interactions with friends, colleagues, and family. Parents know that if they do not keep their promises and carry out their threats, their children will learn to disregard their rules. Moreover...