The Stackelberg vs. Nash-Cournot Folk-theorem in international environmental agreements

A commonly reported result in the literature on international environmental agreements (IEAs) is that if coalition members act as Stackelberg leaders (Stackelberg scenario) this leads to larger stable coalitions than if signatories act simultaneously with non-signatories (Nash-Cournot scenario). This result has been taken for granted, a kind of Folk-theorem, even though it has been proven at best for specific payoff functions, and very often the conclusion is only based on simulations. We prove the Stackelberg vs. Nash-Cournot Folk-theorem based on a generic payoff function for a public good provision game.