Flexible Integration? Mandatory and Minimum Participation Rules
研究欧盟等俱乐部中，允许部分成员形成“内部俱乐部”的灵活合作与强制全体参与的刚性合作孰优孰劣，发现异质性大、外部性小时灵活合作更好，但政治均衡常偏向刚性；并分析了结合强制与最低参与规则的更一般制度的最优与均衡。
Abstract For a club such as the European Union, an important question is whether a subset of the members should be allowed to form “inner clubs” and enhance cooperation. Flexible cooperation allows members to participate if and only if they benefit, but it leads to free‐riding when externalities are positive. I show that flexible cooperation is better if the heterogeneity is large and the externality small, but that rigid cooperation is the political equilibrium too often. Both regimes, however, are extreme variants of a more general system combining mandatory and minimum participation rules. For each rule, I characterize the optimum and the equilibrium.