||The examples and perspective in this article deal primarily with the United States and do not represent a worldwide view of the subject. (October 2011)
In open primary elections in the United States, crossover voting refers to a behavior in which voters who normally participate in the primary of one party instead vote in the primary of another party. The behavior typically happens when the nominee of the one party is a foregone conclusion or when a candidate in one party's primary has an appeal to the voters in another party.
The motives for crossover voting are sometimes strategic. Thus crossover voting has been used by voters to cast votes in the party a voter is opposed to in order to nominate a candidate which can be more easily beaten by the candidate the voter actually supports.
Some consider crossover voting to be a form of electoral fraud.