Nonpartisan primary

A nonpartisan primary, top-two primary, or jungle primary is a primary election in which all candidates for the same elected office run against each other at once, regardless of political party. This distinguishes them from partisan primaries, which are segregated by political party. This is the first round of a two-round system. As opposed to most two-round systems, the "first round" is a primary held before Election Day, and the "second round" is not optional (most two-round systems skip the second round if the winner of the first one gets more than 50%). A two-round system where the first round is held on Election Day is known in the US as runoff voting or top-two runoff.

Advocates claim two-round systems will elect more moderate candidates, as members of a minority party could vote for a more moderate candidate from the majority party, with some political scientists expressing similar views. However, empirical research on the system have found no effect on candidate moderation or turnout among independent voters. A first round with only two winners is also susceptible to vote-splitting: the more candidates from the same party run in the primary, the more likely that party is to lose.

The top-two system is used for all primaries in Washington and California (except presidential primaries). Alaska has used a highly-similar top-four primary with a ranked-choice runoff since the 2022 House special election.