Why Alliances Entangle But Seldom Entrap States

This paper explains one of the central roles of alliance contracts, the prevention of undesirable military entanglement. The existing literature on alliances argues that entrapment is a major concern for potential and actual alliance partners, but it is difficult to point out clear cases of entrapment. I provide two answers to this puzzle: First, entrapment is a narrower concept than others have realized, and it is rarer than the literature suggests. Second, leaders anticipate entrapment and carefully design alliance agreements before and after states form alliances. I examine the second argument through case studies of us alliance agreements with South Korea, Japan, and Spain.