Top two primary

A nonpartisan blanket primary is a primary election in which all candidates for the same elected office, regardless of respective political party, run against each other at once, instead of being segregated by political party. It is also known as a jungle primary,qualifying primary, top-two primary or Louisiana primary.

Under this system, the candidates receiving the most and second-most votes become the contestants in the general election—as in a runoff election, in a two-round system. (In some cases, the second round of voting is necessary only if no candidate receives an overall majority on the initial ballot.) However, there is no separate party nomination process for candidates before the first round, and political parties are not allowed to whittle-down the field using their own internal processes (e.g., party primaries or conventions). Therefore, it is entirely possible that two candidates of the same political party could advance to the general/run-off.

Because voters can vote in the first round for a candidate from any political party, the nonpartisan blanket primary has been compared to the original blanket primary, which was used in Washington for nearly 65 years and briefly in California. The blanket primary was ruled unconstitutional in 2000 by the Supreme Court of the United States in California Democratic Party v. Jones, as it forced political parties to associate with candidates they did not endorse. The nonpartisan blanket primary disregards party preference in determining the two candidates to advance to the general election and for that reason, it has been ruled facially constitutional by the Supreme Court in the 2008 decision Washington State Grange v. Washington State Republican Party.

Chief Justice John Roberts concurred in the 2008 decision, "If the ballot is designed in such a manner that no reasonable voter would believe that the candidates listed there are nominees or members of, or otherwise associated with, the parties the candidates claimed to “prefer,” the I–872 primary system would likely pass constitutional muster." Each candidate for partisan office can state a political party that he or she prefers. Ballots also must feature a disclaimer to voters that candidate's preference does not imply that the candidate is nominated or endorsed by the party or that the party approves of or associates with that candidate.

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