The Top Two Candidates Open Primary Act, which took effect January 1, 2011, created "voter-nominated" offices. The Top Two Candidates Open Primary Act does not apply to candidates running for U.S. President, county central committees, or local offices.

Most of the offices that were previously known as "partisan" are now known as "voter-nominated" offices. Voter-nominated offices are state constitutional offices, state legislative offices, and U.S. congressional offices. The only "partisan offices" now are the offices of U.S. President and county central committee.

All candidates for voter-nominated offices are listed on one ballot and only the top two vote-getters in the primary election – regardless of party preference - move on to the general election. Write-in candidates for voter-nominated offices can only run in the primary election. A write-in candidate will only move on to the general election if the candidate is one of the top two vote-getters in the primary election.

Qualified political parties in California may hold presidential primaries in one of two ways:

Closed presidential primary - only voters indicating a preference for a party may vote for that party's presidential nominee.

Modified-closed presidential primary - the party also allows voters who did not state a party preference to vote for that party's presidential nominee.

If a qualified political party chooses to hold a modified-closed presidential primary, the party must notify the California Secretary of State no later than the 135th day before Election Day. Voters who registered to vote without stating a political party preference are known as No Party Preference (NPP) voters.