American Political Science Review


The Strategy of Ambiguity: Uncertainty and Electoral Competition  *

Kenneth A. Shepsle

Washington University, St. Louis


In this paper problems of social choice in general, and political choice in particular, are considered in light of uncertainty. The space of social alternatives in this formulation includes not only pure social states, but lotteries or probability distributions over those states as well. In the context of candidate strategy selection in a spatial model of political choice, candidate strategy sets are represented by pure strategies—points in the space of alternatives—and ambiguous strategies—lotteries over those points. Questions about optimal strategy choice and the equilibrium properties of these choices are then entertained. Duncan Black's theorem about the dominance of the median preference is generalized, and further contingencies in which the theorem is false are specified. The substantive foci of these results are: (1) the conditions in which seekers of political office will rationally choose to appear equivocal in their policy intentions; and (2) the role of institutional structure in defining equilibrium.

Kenneth A. Shepsle, Assistant Professor of Political Science, Washington University, St. Louis.


*  Several closely related papers including the one presented here have benefitted from close readings and careful criticism by a number of people. For their efforts I acknowledge and thank Richard Niemi, Alvin Rabushka, William Riker, John Sprague, and Herbert Weisberg, as well as the anonymous referees of this paper. A Washington University Faculty Summer Research Grant provided time to prepare and revise various drafts of this paper.