Final answer:
True, a blanket primary allows voters to select from all contenders regardless of party affiliation, differing from closed and open primaries where the process and type of ballot vary.
Step-by-step explanation:
The statement that a blanket primary is a voting process in which voters receive a long ballot containing the names of all contenders, regardless of party, is True. In a blanket primary, voters can select candidates from any party, all of whom are listed on a single ballot. This contrasts with other types of primaries like open, closed, and run-off primaries, where the ballot restrictions and the process differ. For example, closed primaries only allow voters registered with a party to vote for that party's candidates, while open primaries allow voters to choose on election day which party's primary they want to vote in but limit them to choosing candidates from that one party.
Political parties often have concerns with blanket primaries and office block ballots because they can lead to split-ticket voting, where voters may select candidates from different parties. Party-column ballots, in contrast, are preferred by parties as they encourage straight-ticket voting, where voters select all candidates from one party. Therefore, blanket primaries are not commonly used in the United States, with different states having a mix of closed, open, semi-open, and run-off primaries depending on state laws and party preferences.