An Economic Theory of Democracy

An Economic Theory of Democracy is a political science treatise written by Anthony Downs, published in 1957. The book set forth a model with precise conditions under which economic theory could be applied to non-market political decision-making. It also suggested areas of empirical research that could be tested to confirm the validity of his conclusions in the model. Much of this offshoot research eventually became integrated into the Public Choice School. Downs' theory abstains from making normative statements about public policy choices and instead focuses on what is rational, given the relevant incentives, for government to do.

In chapter eight of the book Downs explains how the concept of ideology is central to his theory. Depending on the ideological distribution of voters in a given political community, electoral outcomes can be stable and peaceful or wildly varied and even result in violent revolution. The likely number of political parties can also be identified if one also considers the electoral structure. If the ideological positions of voters are displayed in the form of a graph and if that graph shows a single peak, then a median voter can be identified and in a representative democracy, the choice of candidates and the choice of policies will gravitate toward the positions of the median voter. Conversely, if the graph of ideological distribution is double-peaked, indicating that most voters are either extremely liberal or extremely conservative, the tendency toward political consensus or political equilibrium is difficult to attain because legislators representing each mode are penalized by voters for attempting to achieve consensus with the other side by supporting policies representative of a middle position. Here is a list of the key propositions Downs attempts to prove in chapter eight:

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