Why have militaries so often failed to learn from conflict and war? Why, for example, despite years of unsuccessful counterinsurgency experiences in Vietnam and El Salvador and repeated recommendations from official Army studies, has the U.S. Army not changed its doctrine for counterinsurgency? Writing for scholars as well as military professionals and policymakers, Downie examines the sources of doctrinal change and innovation from a theoretical perspective and derives practical and relevant policy recommendations.

Contrasting with other findings in this field, Downie...