Quite a few Republican crossover voters participated in the Democratic primary.
Mr. Gore needs a big Democratic homecoming, since vice presidents running to keep their parties in power have a hard time attracting crossover voters.
In a nod to potential crossover voters, Mr. Trump at one point on Tuesday quoted Mr. Sanders by name in criticizing Mrs. Clinton.
These are known as "open primaries," and while the party establishment may not like them, it has accepted them in an effort to draw crossover voters who may stick with Republicans in November.
Mr White, keeping his eye on the crossover voters, took a more moderate line that left him, on the issues, looking not all that different from Mr Perry on those issues.
Republicans, Mr Cruz says, lose national elections when they choose moderate candidates who "don't stand and draw a clear distinction, when [they] don't stand for principle".Power without responsibilityPurists of left and right both face a similar problem: neither side has the numbers to win a presidential election without some crossover voters.
In fact, the state now has its unusual "blanket" primary system, in which the names of all candidates appear on the same ballot regardless of party, because a moderate Republican, Representative Tom Campbell, believed he could have won the 1992 primary for United States Senate that he lost to a more conservative candidate if crossover voters had been eligible to participate.
Representative Dawnna Dukes, Democrat of Austin, recently wrote that the interim plan "reduces the voting power of blacks," eliminating a district "where blacks, voting in a coalition with Latino and white crossover voters, were able to consistently elect their candidate of choice to Congress".
The theory was that the law protected black voters who joined with white "crossover voters" to elect a candidate of the black voters' choice.
The absence of a Democratic primary this year could boost participation by crossover voters in the G.O.P. contest.
