A Bargaining Model of Collective Choice

We provide a general theory of collective decision making, one that relates social choices to the strategic incentives of individuals, by generalizing the Baron-Ferejohn (1989) model of bargaining to the multidimensional spatial model. We prove existence of stationary equilibria, upper hemicontinuity of equilibrium outcomes in structural and preference parameters, and equivalence of equilibrium outcomes and the core in certain environments, including the one-dimensional case. The model generates equilibrium predictions even when the core is empty, and it yields a “continuous” generalization of the core in some familiar environments in which the core is nonempty. As the description of institutional detail in the model is sparse, it applies to collective choice in relatively unstructured settings and provides a benchmark for the general analysis of legislative and parliamentary politics.