1920-1993
William Harrison Riker pioneered the use of mathematical reasoning in the study of politics, an approach he termed "positive political theory." The method was positive because of the aspiration to explain observed behavior rather than to make normative prescriptions for how people should behave. It was "theoretical" in the same sense as neoclassical microeconomics in that it used axiomatic methods, especially game theory, to derive a coherent set of propositions that comport with observed behavior.
Riker’s early work focused on the development of theories of legislative behavior. Of particular import was The Theory of Political Coalitions (1962), which used mathematical methods to identify the optimal size of a voting coalition. Previous work suggested that legislators or candidates in election campaigns should work to maximize the number of votes for preferred measures (Downs 1957). Riker’s argument was that this behavior would not be rational in settings, such as the distribution of pork-barrel spending, where resources allocated to the benefit of one actor do not benefit others. Instead, he argued that legislators would prefer to belong to a minimum winning coalition that restricted the number of individuals with a claim to the benefits of a particular program.
Another influential work by Riker, written with the political scientist Peter Ordeshook, was "A Theory of the Calculus of Voting" (1968), which elaborated a rational choice model of voter turnout. They argued that rational citizens should not participate if their goal is to influence election outcomes because the probability that their vote would be decisive is essentially zero. Instead, they argue that the factor motivating participation is the sense of satisfaction people get from performing their civic duty. Critics suggest that Riker and Ordeshook’s model of political participation is evidence of the nonfalsifiability of microeconomic models because the effect of civic duty has the flavor of a post hoc rationalization for why rational citizens participate when they get no benefit in expectation from the activity (Green and Shapiro 1994).
Riker’s later work turned to fundamental questions about the effects of political institutions. In Liberalism against Populism (1982), Riker builds on the intuition from Arrow’s Theorem that democracies are no better than other political systems at achieving socially desirable (pareto optimal) outcomes. He argues that the real value of democratic political systems is not their ability to make good decisions, especially given the possibility of social choice problems, but is instead the public’s ability to punish leaders. In The Art of Political Manipulation (1986), Riker considers how politicians can strategically manipulate the issues they bring to the fore for political advantage.
Riker’s contributions as an institution builder may be even more influential and long lasting than his scholarship. At the University of Rochester in New York, he was given wide latitude to construct a political science department whose faculty and students shared his interest in developing a positive political theory. His success in this endeavor is highlighted by the fact that the Rochester School came to be associated with the body of knowledge derived from the methodological and theoretical orientation Riker advanced, with adherents at almost every major American university. Not wanting to limit the advancement of social science to the study of politics, Riker was instrumental in the formation of the Public Choice Society, which helped positive political theorists form connections with sister disciplines in economics, sociology, public finance, and even philosophy.
