連合政権における政治力学 : ポスト配分を中心に

抄録

l.Introduction 2.Distribution Rules in European Coalition Governments 3.The Liberal Democratic Party as "Faction Coalition" 4.The Case of Japan: Interpretation by Simulation 5.Conclusion In coalition governments, political parties which have another ideology and interests, conflict to handle governments' initiative. The results are seen as payoff of ministries and policy outputs. So the payoff distribution lie at the center of coalition politics. From the point of view, the aim of this paper is to grasp the mechanism that how parties conflict and concert, through the simulation of payoff distribution. In European coalition, ministries are distributed by two conventional norms. The payoff distribution is in proportion to their seats of bargaining power. This bargaining power is measured by Shapley=Shubik value, which is application of game theory. Laver and Schofield pointed out the payoff rules tend to be determined by party system. Turning attention to the case of Japanese coalition governments, Hosokawa, Hata, and Murayama cabinets, I develop three simulations which reconstruct bargaining process. Under four cabinets(including Murayama reshuffle cabinet), "Proportional rule" predicts the actualized payoff better than any other rule. These attempts and results can give new perspective in forming coalition governments.