Switching Equilibria

Abstract

Models of elections typically indicate that all parties, in equilibrium, will adopt positions at the electoral center. This situation, however, is seldom observed. This chapter outlines how an integrated theory of party strategy may be constructed based on a theorem for existence of Local Nash Equilibrium (LNE) in a stochastic electoral model where political agents have differing valence, or electorally perceived quality. In a model based on exogenous valence, it is shown that, under proportional representation, a high valence political leader may be motivated to switch party so as to control a centrist policy position. Under plurality rule, political agents may be forced to switch party as a result of the conflicting demands of activist coalitions.

This chapter is based on work supported by NSF grant 0715929, and a research grant from the Weidenbaum Center, Washington University. The chapter was revised while Schofield was a visiting fellow at ICER, Turin. Versions have been presented at conferences at Trinity College, Dublin, at the University of Virginia, Charlottesville, and at Emory University. The figures are reproduced from Schofield and Sened (2006) with permission of Cambridge University Press.