For a club such as the European Union, an important question is when, and under which conditions, 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 generates a freerider...

I investigate when side payments facilitate cooperation in a context with strategic delegation. On the one hand, allowing side payments may be necessary when one party’s participation constraint otherwise would be violated. On the other, with side payments each principal appoints a delegate...

I study dynamic private provision of public goods (or bads) when agents (or countries) can invest in cost-reducing technologies and sign incomplete contracts. The model leads to a dynamic common pool problem that is more severe than its static counter-part. Nevertheless, a sequence of short-term...

I develop a dynamic model of costly private provision of public goods where agents can also invest in cost-reducing technologies. Despite the n+1 stocks in the model, the analysis is tractable and the (Markov perfect) equilibrium unique. The framework is used to derive optimal incomplete...

I develop a dynamic model of private provision of public bads allowing investments in technologies. The analysis is tractable and the MPE unique. The framework is used to derive optimal incomplete contracts in a dynamic setting. While the noncooperative equilibrium is very inefficient,...

If a coalition of countries implements climate policies, nonparticipants tend to consume more, pollute more, and invest too little in renewable energy sources. In response, the coalition's equilibrium policy distorts trade and it is not time consistent. By adding a market for the right to...

This paper explores how a principal with time-inconsistent preferences invests optimally in technology or capital. If the current principal prefers her future self to save more, she can increase current investments complementary to future savings and decrease investments in the strategic...