Open primaries in the United States

An open primary is a primary election that does not require voters to be affiliated with a political party in order to vote for partisan candidates. In a traditional open primary, voters may select one party's ballot and vote for that party's nomination. As in a closed primary, the highest voted candidate in each party then proceeds to the general election. In a nonpartisan blanket primary, all candidates appear on the same ballot and the two highest voted candidates proceed to the runoff election, regardless of party affiliation. The constitutionality of this system was affirmed by the Supreme Court of the United States in 2008, whereas a partisan blanket primary was previously ruled to be unconstitutional in 2000. The arguments for open primaries are that voters can make independent choices, building consensus that the electoral process is not splintered or undermined by the presence of multiple political parties.

The open primary could be seen as good for voter participation. First, the open primary allows nonpartisan or independent voters to participate in the nominating process. If these voters are allowed to help select the nominees then they may be more likely to vote in the general election, since one of the candidates could be someone the non-partisan voter voted for. Also, a moderate member of one party may agree more with a candidate for the nomination of another party. This voter will have more of an incentive to participate in the general election if there is a nominee whom he or she agrees with.

The open primary could also be viewed as bad for voter participation. Statistics show that voter participation in the United States was higher when people could only vote in the primary for their own party. In Hawaii, primary voter turnout fell from 74.6% in 1978 to 42.2% in 2006 after changing to open primaries which could be the result of many things—not just the move towards the open primary system. The closed primary system had more of an incentive for people to join one of the major parties. This led to people being more involved in the voting process. With the open primary, some argue, more voters become independent and are less likely to participate in the nominating or election processes.

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