Story highlights California Republicans voting this November may not have a Senate candidate from their party on the ballot

That's because the state operates using an open primary, also known as a "jungle primary"

Washington (CNN) It's not looking like a Republican will be on the California Senate ballot in November.

If early vote returns hold, for the first time, California Republicans voting in the general election this November won't have a Senate candidate from their party on the ballot.

That's because the state operates using an open primary -- some people call it a "jungle primary" -- in which only the top two primary vote-getters make it onto the general election ballot, regardless of party. And on Tuesday, not one Republican was poised to make the cut. CNN projected that Attorney General Kamala Harris would get the most votes. Rep. Loretta Sanchez was solidly in second place. So two Democrats had by far the most votes of the 34 ( yes, 34 ) candidates on the ballot. The nearest Republican, Duf Sundheim, was in third with 10% of the vote, reflecting the strength of California's leftward shift over the past generation and setting up a rare Democrat vs. Democrat matchup this fall.

Rep. Loretta Sanchez during an appearance on CNN.

California voters adopted the primary rule change in 2010, and this year marks the first time the state has had an open Senate seat in 24 years. California Sen. Barbara Boxer, who has held the seat since 1993, plans to retire at the end of her term. The other sitting senator, Dianne Feinstein, assumed office about two months earlier, and her term is up in 2018.

With more than 94% of precincts reporting, Harris was in first with 40.4% of the vote, and Sanchez trailed with 18.5%.

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