Party registration choices as a function of the geographic distribution of partisanship: a model of `hidden partisanship' and an illustrative test

The Public Choice literature has identified conditions in which voters in multi-candidate contests would have an incentive to vote strategically rather than vote for the most preferred candidate or candidates. In the US, where party registration and party primaries play a critical role in the electoral process—especially in states with closed primaries—the existence of multiple layers of elections across constituencies can induce strategic falsification of party registration that is tied to the geographic distribution of electoral strength. Following V. O. Key, we should expect that a long history of one party dominance in local elections should encourage voters to register in the party whose elections are most determinative of electoral choices, even if that is not the party with which they most identify. However, in many states, while politics may be dominated by one party locally, there may be real two-party competition for at least some offices at the state level and for the presidency.We use a `natural experiment' to view the link between party registration and voting for president and obscure judicial offices in order to test the hypothesis that, for whichever party is the minority party in the local unit, party registration will understate the voting support in presidential or other statewide elections, where that party's candidates have a realistic chance to win. In the modern South this hypothesis can be shown to imply that the relationship between Republican party registration and vote shares for Republican candidates for president or statewide office ought to be curvilinear. To test this and other related hypotheses, we examine data on political units (e.g. counties) with considerable variation in party registration and concomitant variation in the extent of one-party dominance of local politics by looking at county level data from North Carolina for the presidential elections and obscure judicial elections in 1984 and 1996. As hypothesized, for the North Carolina data the relationship between party registration and voting can best be fit by a quadratic function, but the strength of the quadratic term is much less for the 1996 data, reflecting the increase in Republican registration and the success of local GOP candidates in the 1990s.