Linkage Politics

I extend the basic repeated Prisoners' Dilemma to allow for the linkage of punishment strategies across issues (issue linkage) as well as decentralized third-party enforcement (player linkage). I then synthesize the concepts of issue and player linkage to develop the notion of domestic-international linkage, which allows for the linkage of trigger strategy punishments across games played over different issues by different sets of players. In a two-level game, domestic and international cooperation may be reinforced by a punishment linkage: a defection in the domestic game may trigger a breakdown of international cooperation, and vice versa. I also examine the conditions under which the incentives to cooperate are stronger at the domestic level than at the international level, and vice versa. In this case domestic-international linkage allows for the credibility surplus to spill over to the level with the credibility deficit. Finally, I provide conditions under which governments are better off delinking domestic and international issues.