To Coerce or Reward? Theorizing Wedge Strategies in Alliance Politics

Wedge strategy, a policy of preventing or dividing an adversary coalition, has been attracting increasing scholarly attention. In particular, Timothy Crawford has articulated the concept and claims that reward-based strategies are more effective than coercive strategies that actually strengthen the ties between enemies. Although this sounds logical, history provides sufficient cases that contradict the claim. Why? To answer the question, I develop a theory of wedge strategy by utilizing the concept of reward power. I then argue that although countries seeking to divide adversary coalitions usually prefer reward-based strategies, they turn to coercive measures when a divider state perceives grave threats as a result of a target state's strong alignment with its primary enemy but does not have sufficient reward power to split the adversaries. I examine this theory through two case studies of us wedge strategies toward the Sino-Soviet alliance during the early Cold War period. This article addresses the specific puzzle of choices between reward and coercive wedge strategies and offers broader theoretical implications regarding the utility of the concept of reward power in international and alliance politics.