They call this a closed primary. However, all you have to do is state that you
favor some one party's candidate(s) in order to vote for their slate. You do not have to actually have any proven ties to a party and you can vote however you like in the real election.
An election held to choose candidates for the main election is called a Primary Election.
It's called party raiding
These are called primaries or primary elections. Not all states have them.
These preliminary elections are called primary electionsor primaries. Open primaries allow any registered voter to vote in whatever primary they choose to vote in. Closed primaries attempt to restrict the voters to supporters of the party primary they want to vote in.
Primary Election
An election in which delegates select and nominate candidates is called a caucus.
Those members of public office who are running for re-election are called incumbents.
It's called a primary election because it is the first of more than one election in a particular state for the same term of the same office.
Primary elections or primaries is what these elections are called.
open primary.
runoff primary
Party Nominee - Gov NovaNet