Each political party has the option of allowing people who register to vote without stating a political party preference ("no party preference" voters – formerly known as "decline-to-state" voters) to vote in their presidential primary election. A political party must notify the Secretary of State's office whether or not they will allow no party preference voters to vote in their presidential primary election 135 days before the election.
If a no party preference voter wishes to vote in the presidential primary election of a political party who has notified the Secretary of State that they will allow no party preference voters to vote in their party’s primary, a no party preference voter would simply ask their county elections office or ask a poll worker at their polling place for a ballot for that political party. A voter may not request more than one party's ballot.
If a no party preference voter does not request such a ballot, they will be given a nonpartisan ballot, containing only the names of candidates for voter-nominated offices and local nonpartisan offices and measures to be voted upon at that presidential primary election.
A "closed" primary system governed California's primary elections until 1996. In a closed primary, only persons who are registered members of a political party may vote the ballot of that political party.
The provisions of the "closed" primary system were amended by the adoption of Proposition 198, an initiative statute approved by the voters at the March 26, 1996, Primary Election. Proposition 198 changed the closed primary system to what is known as a "blanket" or "open" primary, in which all registered voters may vote for any candidate, regardless of political affiliation and without a declaration of political faith or allegiance. On June 26, 2000, the United States Supreme Court issued a decision in California Democratic Party, et. al. v. Jones, stating that California's "open" primary system, established by Proposition 198, was unconstitutional because it violated a political party's First Amendment right of association. Therefore, the Supreme Court overturned Proposition 198.
California's current "modified" closed primary system for Presidential elections was chaptered on September 29, 2000 and took effect on January 1, 2001. Senate Bill 28 (Ch. 898, Stats. 2000) implemented a "modified" closed primary system that permitted voters who had declined to provide a political party preference (formerly known as "decline to state" voters) to participate in a primary election if authorized by an individual party's rules and duly noticed by the Secretary of State.
The Top Two Candidates Open Primary Act, which took effect January 1, 2011, requires that all candidates for a voter-nominated office be listed on the same ballot. Previously known as partisan offices, voter-nominated offices are state legislative offices, U.S. congressional offices, and state constitutional offices. Only the two candidates receiving the most votes—regardless of party preference—move on to the general election regardless of vote totals.
Write-in candidates for voter-nominated offices can only run in the primary election. However, a write-in candidate can only move on to the general election if the candidate is one of the top two vote-getters in the primary election.
Additionally, there is no independent nomination process for a general election. California's new open primary system does not apply to candidates running for U.S. President, county central committee, or local offices.
Under the California Constitution, political parties may formally nominate candidates for party-nominated/partisan offices at the primary election. A candidate so nominated will then represent that party as its official candidate for the office in question at the ensuing general election and the ballot will reflect an official designation to that effect. The top votegetter for each party at the primary election is entitled to participate in the general election. Parties also elect officers of official party committees at a partisan primary.
No voter may vote in the primary election of any political party other than the party he or she has disclosed a preference for upon registering to vote. However, a political party may authorize a person who has declined to disclose a party preference to vote in that party's primary election.
Under the California constitution, political parties are not entitled to formally nominate candidates for voter-nominated offices at the primary election. A candidate nominated for a voter-nominated office at the primary election is the nominee of the people and not the official nominee of any party at the following general election. A candidate for nomination or election to a voter-nominated office shall have his or her party preference, or lack of party preference, reflected on the primary and general election ballot, but the party preference designation is selected solely by the candidate and is shown for the information of the voters only. It does not constitute or imply an endorsement of the candidate by the party designated, or affiliation between the party and candidate, and no candidate nominated by the qualified voters for any voter-nominated office shall be deemed to be the officially nominated candidate of any political party. The parties may list the candidates for voter-nominated offices who have received the official endorsement of the party in the sample ballot.
All voters may vote for any candidate for a voter-nominated office, provided they meet the other qualifications required to vote for that office. The top two votegetters at the primary election advance to the general election for the voter-nominated office, even if both candidates have specified the same party preference designation. No party is entitled to have a candidate with its party preference designation participate in the general election unless such candidate is one of the two highest votegetters at the primary election.
Under the California Constitution, political parties are not entitled to nominate candidates for nonpartisan offices at the primary election, and a candidate nominated for a nonpartisan office at the primary election is not the official nominee of any party for the office in question at the ensuing general election. A candidate for nomination or election to a nonpartisan office may not designate his or her party preference, or lack of party preference, on the primary and general election ballot. The top two votegetters at the primary election advance to the general election for the nonpartisan office.