This book introduced a leader- centered theory of foreign policy change and applied said theory to examine changes in U.S.–Cuba policy during the Obama administration. This concluding section proceeds in three steps. It first summarizes the argument of the book. It then briefly explores the extent to which the proposed theory can account for additional changes, in the form of reversals of Obama's policy changes, that were introduced by his successor Donald Trump. The discussion concludes with avenues for future research.

Summary of the argument

Leaders are commonly associated with and held responsible for fundamental changes in the foreign policy of their countries. In this sense, George W. Bush started the war in Iraq, Chinese foreign policy became much more coercive under Xi Jinping, and Vladimir Putin decided to invade Ukraine. However, and somewhat surprisingly, the academic literature on foreign policy change has so far placed limited emphasis on the role of leaders as key agents of policy change. This is not to say that leaders have been ignored altogether. However, as outlined in Chapter One of this volume, analytical frameworks typically combine a host of both structural and actor- oriented factors in their explanations of episodes of major foreign policy change. What is largely missing are frameworks that would allow to discern any independent, systematic, and predictable effect of individual leaders on such processes.

To that end, this volume has introduced a “leader- centered theory of foreign policy change” in Chapter Two which seeks to account for major changes in a country's foreign policy. Following the definition of Charles Hermann (1990), such kinds of changes do not come in one- off decisions nor are they confined to a specific issue area but rather comprise substantial changes in both rhetoric and actions, include a succession of decisions, and span multiple issue areas. The theory suggests that leaders have a systematic, independent, and predictable effect on the substance and the direction of such processes. Those effects concern the “why,” “what,” and “how” of foreign policy change.

The “why” relates to the reasons why leaders seek to fundamentally reorient their countries’ foreign policy (“triggering change”), which the theory connects to leaders’ diagnosis of failure of existing policies.