Even powerful states face disaster if their armies do not adapt military doctrine to meet new challenges. Comparing the cases of the United States Army in Vietnam and the British Army during the Boer War and the Malayan Emergency, Political Institutions and Military Change offers an account of the conditions that help shape doctrine within military organizations. Drawing on the new institutional economics, Deborah D. Avant assumes that actors at every level will seek to enhance their political power. Military organizations will thus respond to civilian goals when military leaders expect rewards for their responsiveness. Tracing the evolution of civil-military relations in the United States and Britain, Avant highlights that a nation's political structure has a major impact on the structure of military organizations and their formation of military doctrine. Political Institutions and Military Change discusses how the structural differences between the British and US governments resulted in very different biases within the two armies, and how their political conditions and systems contributed to the relative ease with which the British Army adapted to new peripheral threats and the reluctance with which the US Army responded to change in Vietnam.