CONCEPTUALIZING CROSSOVER VOTING

Crossover voting is, on its face, a simple notion: voting for a candidate outside of one's political party. However, this basic definition masks several more complicated issues (see Wekkin 1988). First, how should the political

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party to which a person belongs be defined? One possibility is party registration. Under this definition, voters cross over when they vote for a candidate from a party other than the one in which they are registered. The blanket primary, in doing away with the party primary, makes party registration electorally superfluous. There is effectively only one primary, and any registered voter can participate fully.^[2] The virtue of defining crossover voting based on party registration is that one can estimate what would likely have happened had the California primary still been closed. That is, one can "separate" the winning candidate's vote share received from minor-party, nonpartisan, and crossover voters, and then, given certain assumptions, gauge the chances of his or her winning this simulated primary. Defining crossover voting in terms of party registration therefore provides useful counterfactual comparisons across electoral regimes.

Another alternative is to define crossover voting based on party identification. Whereas party registration is a legal formality, party identification is a psychological construct, an enduring tie between a citizen and a particular political party. Party identification does not entirely determine one's vote, and therefore affiliating with a party is conceptually distinct from voting for that party's candidate (Miller and Shanks 1996). Nevertheless, if party identification constitutes, in V. O. Key's phrase, a "standing decision," then voting against one's normal affiliation in the absence of any strategic consideration implies a weakening of loyalty, either temporary or permanent. Because voters vary in the intensity of their party identification, defining crossover voting with this as the reference point allows for a deeper analysis of its underlying psychology, since one can compare strong and weak partisans.

Another definitional issue concerns the self-styled political independent. In the case of party registration, "independents" include both members of minor parties and those who do not register with any party ("nonpartisans").^[3] In the case of party identification, "independents" profess no attachment to any party. Strictly speaking, any independent (however defined) who votes for a Democrat or Republican engages in crossover voting (Adamany 1976). Under California's closed primary system, major-party primaries were restricted to voters registered in those parties, and minorparty members, nonpartisans, and members of the opposing major party could not participate. A blanket primary system effectively enfranchises these groups and thus creates a population of nonparty members who can vote for a major party's candidates.^[4] However, because Democratic and Republican party officials worry mostly about potential mischief by the major opposition party, not about the votes of minor-party members and nonpartisans, we focus primarily on crossover voting among Democrats and Republicans.

In California, party registration and party identification are closely interrelated.

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When the respondents from the four Field polls conducted before the primary are pooled (N ? 4,060), 91 percent of both registered Republicans and registered Democrats had a consonant party identification.^[5] A similarly strong relationship emerges when we construct measures of crossover voting.^[6] These variables are simply dichotomous, coded 1 if a respondent crossed over (i.e., a registered Republican or a Republican party identifier voted for a Democratic candidate, and vice versa) and 0 if not. In the case of crossover voting for Governor, the correlation between these two measures was .75. In the U.S. Senate race, the correlation was .71. Crosstabulating the two measures demonstrates that 93 percent of party identifiers who intended to cross over in their vote for Governor also intended to cross over vis-à-vis their party registration (the comparable figure for the Senate race was 91 percent).