Voting in America varies from state to state as each holds different laws for factors such as registration and which voters may participate in primaries. Moreover, these rules often differ for congressional/state and presidential primaries.
Primaries fall into one of three categories with regard to voter eligiblity: Closed, Open Partisan, and Open Nonpartisan.
Only voters who are officially registered with a party may vote in that party's primary election. Also, their own party's primary election is the only one in which a voter may vote (Ex: Only voters registered as Republicans may vote in the Republican primary, and they may not vote in the Democratic primary).
Voters who are already registered with a party may vote in that party's primary election—and only that party's election (same as a closed primary). However, independent voters who are not registered with any party may also vote in any party's primary, though they may only vote in one party's primary each election cycle (Ex: A voter not registered with either party may vote in the Republican or Democratic primary, but not both).
All voters may vote in any party primary regardless of their registration status, but may still only vote in one primary per election cycle. For example, a voter registered as a Republican may forego the Republican Primary and instead vote in the Democratic (or Libertarian, or any other party) primary if they prefer, but they could not then also vote in the Republican primary.
As mentioned, these rules are up to each state and, in some cases, are up to each party. When looking to vote in your state, be sure to do your research. Some states have made amendments in 2022 to make voting more or less open.
For example, New Mexico has begun to allow unaffiliated voters to participate in primary votes by allowing them to show up to the polls and change their registration status.
Washington and California have what is known as a top-two primary. This type of primary election lists all candidates on the same primary ballot and the top two candidates, regardless of their partisan affiliation, advance to the general election.
California has a modified closed primary between 2001 and 2011, which allowed each political party to decide whether they would permit unaffiliated voters to vote in their primary.
This system eased the constitutional concerns of both the open and closed primary systems. The Republican, Democratic, and American Independent parties all chose to permit unaffiliated voters to request their party’s ballot in the 2004 and 2006 primaries, but the Republican Party has not opted for this since the 2008 presidential election.
In 2011, California adopted a modified open primary, allowing individual citizens to vote for any candidate, and the top two candidates, regardless of party, advance to the general election. This method is a contest for state delegates and is not used for the Presidential election.
Supporters of open primaries argue that open primaries could increase voter participation as there are fewer restraints on your options. Open primaries allow nonpartisan or independent voters to nominate presidential candidates, making them more likely to vote in the general election. Also, someone in the middle may agree more with a single candidate of one party and encourage them to vote in the open primary and general elections.
On the other hand, opponents of the open primary system argue that it is bad for voter participation since the closed primary system has more incentive for people to join one of the major parties.
Opponents also argue that the open primary could lead to dilution and manipulation if one party plans to have its voter vote in the other party’s primary. In this event, voters could choose the less desirable or the one that could be easily defeated by the first party.
Additionally, opponents argued that the open primary is unconstitutional because it violates their freedom of association. This is because open primaries allow outsiders of their party to select their candidates. To counter this argument, supporters argue that the U.S. Constitution does not mention political parties.