Soc Choice Welfare (1987) 4:117-131 S0cial Ch0ice .dWelfare © Springer-Verlag 1987 A Group Majority Voting Model of Public Good Provision* R. B. Morton Department of Economics and Finance, Nicholls State University, P:O. Box 2015, Thibodaux, LA 70310, USA Received February 13, 1986/AcceptedDecember26, 1986 Abstract. A model of public good provision by majority rule selection incorporating the behavior of rational group voting is formulated. Two probability maximizing candidates are assumed. If voters are risk averse in public sector preferences, then a unique symmetric (both candidates offering identical platforms) equilibrium exists. If certain additional conditions hold on the group cost functions of political support, this equilibrium will lie at the public good level which maximizes the sum of voter utility. It is further demonstrated that it is unlikely for those conditions to be satisfied and therefore more realistic asymmetric equilibria with positive voter turnout is predicted: A. Introduction As Ledyard (1984) has pointed out, one of the tasks public choice theorists have attempted to accomplish is the building of a theory of majority rule selection of public good provision which is based upon rational behavior and is non-vacuous. He notes that two voting paradoxes have generally stood in the way of the development of such a theoretical framework: 1) the instability of the pure majority rule system (PMR) and 2) the lack of a rational individual level explanation for voter turnout and choice. Both paradoxes strike at the heart of any rigorous attempt to model majority rule choice of public good levels from an "economic" approach. Equilibrium analysis is the primary tool used by economists for explanation and prediction of events. It is considered by some researchers the characteristic of economics which distinguishes it from all other social sciences. [See Riker (1980) for example:] Equilibria are used to compare allocation systems in terms of efficiency and welfare maximization. Is it possible for the majority rule allocation of public * This paper is based on an essay of a dissertation submitted to Tulane University under the supervisionand invaluableassistanceof StevenSlutsky,Jonathan Hamilton,and WilliamOakland. The adviceof Gerald Whitney,MichaelJohnson,and an anonymous referee is also gratefully acknowledged: All errors remain the authors.