Turning it over to elections reporter Robert Yoon for a preview of this week's primary blitz:
The big picture: California’s primary for governor — with its top-two/all-party format, 61 candidates, frequent lead changes and a touch of scandal — might be the most widely talked about race on the ballot Tuesday, but it’s just one of more than 300 contests voters will decide in seven states.
Here are some of the notable races on the docket in Arkansas, California, Iowa, Montana, New Jersey, New Mexico and South Dakota:
Governors: California is still the night's marquee gubernatorial race, but beyond the Golden State's borders, retirements and term-limits have created open seat primaries in Iowa and New Mexico.
In the latter, former Biden Interior Secretary Deb Haaland looks to become the first Native American woman to serve as governor of any state. In South Dakota, former Republican Gov. Kristi Noem’s successor, Larry Rhoden, is trying not to join a rather exclusive club: incumbent governors who lose their primary. He would be the sixth of this millennium.
U.S. Senate: The race to succeed retiring Republican incumbent Joni Ernst has steadily crept into Democratic calculations to retake the chamber. Two Democratic Iowa state legislators are in a competitive race for the nomination, and Trump has endorsed U.S. Rep. Ashley Hinson in the GOP primary.
Trump and retiring Republican incumbent Steve Daines have backed Kurt Alme in Montana's GOP primary. If he wins, he’d face the winner of a crowded Democratic primary, plus a well-funded independent candidate, Seth Bodnar.
U.S. House: Tuesday’s primaries in California, Iowa and New Jersey will set the table for some of the midterms' most competitive House races.
California’s first primary using a new, Democratic-friendlier map put the state’s Republican incumbents in a tough spot — especially U.S. Reps. Ken Calvert and Young Kim, who are running against each other in CA40. U.S. Rep. Kevin Kiley quit the GOP and will run in the general as an independent in CA06. Plus, Bay Area Democrats will nominate a successor to former Speaker Nancy Pelosi.
Down ballot: Notable local races include an increasingly reality show-styled Los Angeles mayoral election, state legislative grudge matches in Montana, unopposed New Mexico write-in candidates who each must receive a specific number of votes to advance to the general, and a special legislative primary in Arkansas.
Read more from Yoon on contests in California, Iowa, Montana & more.