In summary

There are different rules for the presidential contest and state races on the March 5 ballot. And each party has its own rules.

No wonder a lot of California voters are confused about how to cast ballots in the March 5 primary. It’s really two primaries wrapped into one, with two different sets of rules.

For the U.S. Senate, U.S. House and state legislative races, California holds an “open” primary.  Voters, no matter how they’re registered, can pick anyone of any party.

Which means, for instance, that you don’t have to be a registered Republican to vote for a Republican candidate in the U.S. Senate primary — you can do that if you’re registered with no party preference or another party, even if you’re a Democrat.

And if you want to vote for one of the Democrats in the race, you’ll have that option even if you’re a registered Republican.

The top two vote-getters, regardless of party affiliation, advance to the November general election.

But it’s different for the presidential primary.

You can only cast a ballot on the Republican side — at this point, basically a choice between frontrunner Donald Trump and challenger Nikki Haley — if you are registered in California as a Republican. The state GOP has chosen to stage a “closed” presidential primary, which also means that voters registered with no party preference cannot participate. (The same applies to the Green and Peace and Freedom parties). 

But the California Democratic Party allows even voters who aren’t registered Democrats to vote in its presidential primary — although there’s a catch. Unaffiliated voters — who are otherwise set to receive ballots that don’t have the presidential race on it — will need to request a ballot that includes the presidential race. (The American Independent and Libertarian parties also allow no party preference voters.)

To change your party registration, you’ll need to re-register to vote. The last day to register online for the primary is Feb. 20. If you are registering or re-registering less than 15 days before March 5, you must complete same-day voter registration and request your ballot in person at your county elections office or polling location.

In all, you can vote for one of 23 official presidential candidates, but only for those on your party’s ballot. Also, you can vote for one of 14 certified write-in candidates, but only if you have the ballot for that person’s party.

Have more questions about voting? You’ll find answers in CalMatters’ 2024 Voter Guide.