We consider a voluntary contributions game, in which players may punish others after contributions are made and observed. The productivity of contributions, as captured in the marginal-per-capita return, differs among individuals, so that there are two types: high and low productivity. Every two...

We consider collective decisions made by agents whose preferences and power depend on past events and decisions. Faced with an ineffcient equilibrium and an opportunity to commit to a policy, can the agents reach an agreement on such a policy? Under an intuitive condition linking power...