Book excerpt: In the years since the 9/11 attacks, socially constructed understandings of the identity of the United States and its friends and enemies in the world have played a critical role in determining the course of U.S. foreign policy. Constructing Twenty-First Century U.S. Foreign Policy argues that American foreign relations under the Bush administration were driven by an ideological agenda derived from a particular interpretation of long-standing ideas about national identity. Drawing on constructivist and social-psychological IR theory, it suggests that these ideas led directly to the administration's choice to invade Iraq, its misunderstanding the kind of war the United States would face there, and its failure to quickly establish a stable democratic government following the invasion.