I. Until about a dozen years ago, the economic analysis of the relationship between political preferences and political demands was a rather straightforward, if dull, subject. The most common assumption was that the only political instrument available to citizens was the vote. Given this assumption, the analyst could express the outcome of the voting process in one of two ways. One possibility was to make the heroic assumptions necessary to obtain the median voter theorem, in which case, the political demands of the citizenry are simply the preferences of the median voter. The alternative was to make Arrow's Impossibility Theorem in which case even though individual preferences are well ordered, no collective preference function exists. On either of these approaches, institutions such as interest groups, political parties, or the structures ofpolitical representation played no role in the analysis. The work of "Chicago" scholars especially George Stigler, Gary Becker and Sam Peltzman took a different approach and emphasized the importanceoforganizationinmakingpoliticaldemandseffective, shifting thefocus from voting topolitical "pressure" byinterestgroups. However, in these models, voting as an instrument of political action simply disappears and the relationship between interest group pressures and electoral processes has never been clarified.

I. Until about a dozen years ago, the economic analysis of the relationship between political preferences and political demands was a rather straightforward, if dull, subject. The most common assumption was that the only political instrument available to citizens was the vote. Given this assumption, the analyst could express the outcome of the voting process in one of two ways. One possibility was to make the heroic assumptions necessary to obtain the median voter theorem, in which case, the political demands of the citizenry are simply the preferences of the median voter. The alternative was to make Arrow's Impossibility Theorem in which case even though individual preferences are well ordered, no collective preference function exists. On either of these approaches, institutions such as interest groups, political parties, or the structures ofpolitical representation played no role in the analysis. The work of "Chicago" scholars especially George Stigler, Gary Becker and Sam Peltzman took a different approach and emphasized the importanceoforganizationinmakingpoliticaldemandseffective, shifting thefocus from voting topolitical "pressure" byinterestgroups. However, in these models, voting as an instrument of political action simply disappears and the relationship between interest group pressures and electoral processes has never been clarified.

I. The concept of competition played a central role in the very first attempts to apply the tools of economics to the analysis of politics. Adopting Hotelling's (1929) industrial organization model of imperfect competition in markets in which space has a predominant role, Downs (1957), following on some perceptive insights of Schumpeter (1942), was able to formulate a model of electoral competition in which political parties, seeking the support of citizens, compete against each other in offering policies designed to elicit their vote. Downs' model and the numerous variants to which it gave birth soon became the major component of what was to become Public Choice Theory. The enormous efforts of the last 30 years devoted to modelling electoral competition have helped improve our understanding of politics and have contributed a basic element that undoubtedly will remain essential to any reasonably complete theory of politics. But whatever may have been early expectations, it is now clear that electoral competition will only be one such element. More recently, the idea of competition has been used to model interest-group behavior. Becker (1983), building on earlier work by Bentley (1908), Truman (1958), Olson (1965), Stigler (1971) and Peltzman (1976), applied the Public Finance analysis of the excess-burden of taxes and subsidies - to which, incidentally, Hotelling (1938) had made pioneering contribution- to produce a model in which competition between interest groups determines an equilibrium distribution of income.