Between the role of home territory and the impact of non Republican crossover voters, it will be difficult to evaluate how significant the size of his plurality is.

The absence of a Democratic primary this year could boost participation by crossover voters in the G.O.P. contest.

Not suprisingly, Mr. McCain appeals again and again to potential crossover voters.

Instead of shoring up support among Southern whites, it may turn many into crossover voters, more interested in the race on the Republican side.

In politics, a crossover voter is one registered in one party who votes in the opposing party's primary election.

The state Republican Party has a huge operation dedicated to identifying the crossover voters, sending them mail and urging them to the polls.

There are huge numbers of crossover voters.

Ultimately, Grusendorf blamed his defeat on Democratic crossover voters who had not previously participated in Republican primaries in Tarrant County.

Mr. Checchi is betting on change, and Republican and independent crossover voters.

"Many of the crossover voters that would have gone to Buchanan were probably absorbed by Jerry Brown," Mr. Erikson said.