In this timely study, Mara E. Karlin challenges the U.S. government's default position that the secret to successful foreign military assistance is “more”—that is, “More equipment. More training. More help. More quickly” (p. 2).

Karlin is well qualified to do so. Before joining the faculty of the Johns Hopkins University School of Advanced International Studies in 2017, Karlin served in the Pentagon's Office of the Under Secretary of Defense for Policy, where she helped run several military assistance programs on behalf of the U.S. military.

In this book, Karlin argues that success—which she defines as a “more enforced and sustainable monopoly on violence extended by the partner state” (p. 11)—is a function of two main variables. The first is the donor state's degree of influence over the leadership and structure of the partner military (their “sensitive military affairs”). The second is the degree to which external, third-party actors undermine the capacity-building effort. Success is most likely in cases in which the donor gets deeply involved in the sensitive military affairs of its partner—without becoming a co-combatant—and the influence of antagonistic external actors is either absent or diminishing over time. When one or the other of the