Under what conditions should we expect states to do things radically differently all of a sudden? In this book, David Welch seeks to answer this question, constructing a theory of foreign policy change inspired by organization theory, cognitive and motivational psychology, and prospect theory. He then "test drives" the theory in a series of comparative case studies in the security and trade domains: Argentina's decision to go to war over the Falklands/Malvinas vs. Japan's endless patience with diplomacy in its conflict with Russia over the Northern Territories; America's decision to commit large-scale military force to Vietnam vs. its ultimate decision to withdraw; and Canada's two abortive flirtations with free trade with the United States in 1911 and 1948 vs. its embrace of free trade in the late 1980s.