I have been describing the changes in store for my textbook on Formal Models of Domestic Politics. Let me now turn to the three opening chapters: electoral competition under certainty, electoral competition under uncertainty, and special interest politics (the last of these substantially but not only applied models of electoral competition).

The formal analysis of elections was among the first applications of game theory to the study of politics. The field is well developed, and at times it seems there must not be much more to say. In fact, the study of elections has been reinvigorated with the incorporation of assumptions about parties' (or candidates') "immutable" characteristics--their honesty or competence, for example--which both intuition and empirical evidence suggest citizens weigh in deciding how to vote. When voters' preferences over these characteristics are homogeneous and separable from their preferences over policy, we say that parties may possess a "valence" advantage. Numerous models explore platform choice in the presence of such advantages. I discuss some key findings briefly as an exercise in the chapter on electoral competition under certainty, and then more extensively in the following chapter on electoral competition under uncertainty.

The real payoff from this approach, in my opinion, comes when we drop the assumption that preferences over parties' immutable characteristics and preferences over policy are separable. Consider a phenomenon well known to students of political behavior: the "ownership" of issues by one party or another. In the context of American politics, for example, the Republican Party historically has been more trusted on national defense, the Democratic Party more on education and healthcare. This is not about a party's general competence but about its competence in producing some policy outcomes over others.

Stefan Krasa and Mattias Polborn have an elegant model of electoral competition with issue ownership; it is the most substantial addition to the first three chapters of Formal Models of Domestic Politics. The environment is straightforward--voters differ in the weight they place on different public goods; parties differ in their efficiency in providing those goods, to which they allocate more or less spending--but equilibrium behavior is truly surprising for anyone schooled in the Downsian tradition. Parties propose distinct bundles of public goods, even though they are office-seeking rather than policy-seeking, with each party providing more of the good that it produces more efficiently. And the positions they adopt are independent of uncertainty about voters' preferences. Shift the expected median to the right or the left, and parties stay put; it is their probability of winning that changes, not their platforms. Applied to American politics, one can see the dilemma of the GOP in the face of changing demographics: so long as voters as constant in their evaluation of parties' ownership of various issues, no shift in platform can prevent the erosion of support among an electorate increasingly attuned to "Democratic" issues.

There is, of course, another tradition of modeling elections as a mechanism for selecting politicians according to their type: the formal analysis of "political agency," in which an incumbent politician plays agent to voters' principals. But that is another chapter, a topic for another post.