Special Interest Politics and Endogenous Lobby Formation

We analyze endogenous lobby formation within a slightly modified version of the “special interest politics” model of Persson (1998). In our model the interest groups hold different fixed endowments of an ”infrastructure good” which is a complement in consumption of the local public good. For any fixed set of organized groups the lobbying game is shown to have a unique equilibrium if the cost-elasticity of the supply of public good to the interest groups by the government is not too large. The groups which benefit from larger infrastructure endowments are then proved to be the ones which become organized while the others remain unorganized.