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, Deborah D. Avant offers a new account of the conditions that help shape doctrine within military organizations.

Drawing on the new institutional economics, 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 concludes that a nation's political structure has a major impact on the structure of military organizations and their formation of military doctrine.

Avant finds in particular that structural differences between the British and U.S. governments have resulted in very different biases within the two armies. Unified political institutions in Britain worked to create an army that was sensitive to civilian goals and enabled civilian leaders to intervene to force military change. Conversely, the U.S. political system tended to allow adherence to classic principles of military science within the Army and often impeded effective civilian intervention.

These contrasting conditions contributed to the relative ease with which the British Army adapted to new peripheral threats and the reluctance with which the U.S. Army responded to change in Vietnam.