We develop a model that combines competitive exchange of private commodities across endogenously formed groups with public good provision and global collective decisions. There is a tension between local and global collective decisions. In particular, we show that group formation and collective...

We introduce democratic mechanisms where individual utilities are not observable by other people at the legislative stage. We show that the combination of three rules can yield e±cient provision of public projects: first, flexible and double majority rules where the size of the majority depends...