What Is an Open Primary?

An open primary is a primary election that doesn't require voters to be officially affiliated with a particular party. Or, it is an election that lets a voter change their party affiliation before voting.

An open primary differs from a closed primary, which requires a voter to declare a party affiliation before voting. A semi-closed (or hybrid) primary allows unaffiliated voters to vote any way they wish. However, affiliated voters must vote with their party.

Open Primary Allowed in 22 States

Twenty-two states allow open primaries for at least one political party. They are:

• Alabama
• Alaska
• Arkansas
• Georgia
• Hawaii
• Illinois
• Indiana
• Iowa
• Michigan
• Minnesota
• Mississippi
• Missouri
• Montana
• North Dakota
• Ohio
• South Carolina
• Tennessee
• Texas
• Vermont
• Virginia
• Wisconsin
• Wyoming

In all but two of those states, every political party conducts open primaries.

Pros and Cons to Open Primaries

Open primaries share roots with primary elections in general. Rather than allowing party caucuses to name a presidential nominee, progressive reformers of the early 20th century:

• Pushed to give voters more say over a party's nominee via primary elections
• Later gave voters more say in open primaries

One advantage of open primaries is that they discourage partisan "gridlock," in which voters are forever tied to their registered party. Open primaries can also serve the purpose of:

• Enticing voters to the polls who aren't registered with any party
• Widening the field of prospective nominees within the party

Opponents of open primaries say they leave open the possibility of "crossover" voting. In other words, a registered Republican in a state that allows open primaries might cast a primary vote for the most conservative Democratic candidate. This can skew the party's nomination process.

That happened in the 2008 New Hampshire presidential primary election, in which Mitt Romney won among registered Republicans, but John McCain won overall.

Freedom to Vote How You Want

Despite ongoing controversy, open primaries remain a popular way to let primary voters cast a ballot for the candidate they like, and not necessarily the party they're registered with.