Ally provocateur: Why allies do not always behave

The primary purpose of many alliances is to deter attacks on members of the alliance by potentially antagonistic states. Yet some alliances can increase the probability of conflict that may be initiated by alliance members. Cognizant of that possibility, states that wish to sustain peace may nevertheless intentionally form alliance commitments with revisionist leaders of other states. Faced with the partially conflicting goals of deterring antagonistic states while at the same time restraining allies, leaders often include in alliance treaties conditions that oblige allies to provide military assistance only if a member of the alliance is attacked by a state outside the alliance. However, other treaties may contain unconditional obligations to come to the defense of members of the alliance. Such alliances tend to arise from situations where some members of the alliance feel that their alliance partners need to have the flexibility even to engage in provocative behavior in order to deter the target of the ...