International Cooperation, Parties and Ideology

Abstract: I combine a model of international cooperation with a model of domestic politics with primaries and national elections between candidates of two different parties. International cooperation is modeled as a repeated prisoner’s dilemma game between two countries. I compare four different types of equilibria. In the country specific grim trigger equilibrium, domestic politics does not affect international cooperation and the standard results for the repeated prisoner’s dilemma game apply. The second equilibrium is based on Mcgillivray’s and Smith’s(2008) idea of leader specific punishment. If a prime minister cares sufficiently about staying in office, the threat of replacing him in a primary if he does not cooperate internationally can change a politician’s incentives and make a larger maximum equilibrium level of cooperation possible. I introduce two new types of equilibrium to the literature that are specific to my model. In the case of party specific punishment without international dominance, as punishment for a deviating on the international level,prime ministers are not only replaced, but in addition the party to which the prime minister belongs loses power. This increases the severity of punishment and consequently increases the maximum possible level of international cooperation. However, voters are only able to commit to such a strategy if maximum equilibrium level of international cooperation is large enough to justify replacing a popular prime minister. In the case of party specific punishment with international dominance, the voters always reelect a prime minister who cooperates internationally, even if they prefer the candidate of the other party ideologically. In this setting, a deviating politician loses office forever instead of keeping it forever. Consequently, the maximum achievable level of international cooperation is very large, but elections no longer lead to the victory of the candidate preferred by the majority of voters.