California Republicans, get ready to matter!

The party that hasn’t elected anyone to statewide office in a decade just might get the last word on whether Donald Trump should be the GOP’s presidential nominee — not to mention a front-row seat to a huge political spectacle that will likely trigger massive protests.

The New York real estate titan is the only Republican left who has a plausible shot at securing the necessary 1,237 delegates for the July convention, but he likely can’t do it without a strong showing in California on June 7.

With the candidates competing for three delegates in each of California’s 53 congressional districts — and another 13 for winning the statewide vote — Trump will have to close the deal with voters from Siskiyou County all the way down to the border, where he wants to build a “beautiful wall.” And he will have to fend off a challenge on the right by Texas Sen. Ted Cruz and on the left by Ohio Gov. John Kasich, who beat Trump in his home state Tuesday.

“What we can see from here on out is a two-front war where Kasich needs to steal delegates from Trump in blue districts and Cruz needs to steal votes in red districts,” said David Wasserman of the highly respected Cook Political Report.

If the strategy succeeds in denying Trump enough delegates, Republicans will pick a nominee at their national convention in July. That could result in a candidate with better odds of winning in November, but it also could tear the party apart if the top vote-getter — most likely Trump — doesn’t get the nomination.

Trump warned Wednesday that the GOP faced major repercussions if he doesn’t get the nomination. “I think you’d have riots,” he told CNN. “I’m representing many, many millions of people.”

Trump’s victories in Florida, Missouri, Illinois and North Carolina on Tuesday currently leave him with 673 delegates to Cruz’s 411 and Kasich’s 143. In the Democratic race, Hillary Clinton swept all five states, giving her a seemingly insurmountable delegate lead over Vermont Sen. Bernie Sanders.

Wasserman estimates that Trump will need to win 53 percent of the remaining 1,000 or so delegates to secure the Republican nomination, including about 94 of California’s 172 delegates.

“I think it’s highly achievable,” Wasserman said, explaining that before Tuesday, Trump’s delegate hauls were limited by GOP rules that require most early primary states to award delegates based on a candidate’s share of the vote. But going forward, Wasserman said, most states will award delegates on a winner-take-all basis — based either on the statewide vote or the vote in each of a state’s congressional districts.

“You just need to imagine congressional districts as mini-states,” Wasserman said.

That new format helped Trump pad his delegate lead this week. Even though Trump beat Cruz by less than a percentage point in Missouri, Wasserman said, Trump will end up with 37 to 42 of the state’s 52 delegates because he narrowly won most of the state’s congressional districts.

Overall, Wasserman said, Trump stood to win more than 60 percent of the delegates on Tuesday even though he received only about 40 percent of the vote.

Not everyone is high on Trump’s chances of heading to the convention in Cleveland as the winner.

Bill Whalen, a Hoover Institution research fellow and longtime GOP strategist, crunched some numbers this week and found Trump falling about 100 delegates short. But, he added, Trump might have a silver bullet in his arsenal.

“There is a way to get over the top — and that is California,” he said.

But the Golden State — which will account for more than half of the delegates awarded when California and four other states vote on June 7 — presents problems for Trump: The GOP primary is only open to registered Republicans, who have been less bullish on Trump than independent voters.

Trump also will have to deal with a Cruz campaign that has been on the ground organizing for months and a Kasich campaign that could rake in Silicon Valley money and poll well in more moderate areas.

“Trump’s plan has been to have really no ground game, but California is a different animal,” Whalen said. “You’re talking about 53 different congressional districts at once. If you’re Trump, and you’re looking for the knockout punch, you need to come out here and organize because that is what Cruz is doing.”

If Trump goes all in here, registered Republicans should expect a raft of robocalls and emails. And everyone should brace for TV attack ads galore.

“All those people who complain we get ignored because we’re not a battleground state are now going to be sorry,” said Samuel Popkin, a political science professor emeritus at UC San Diego. “I hope they’ll understand how blessed we were.”

Popkin expects Trump to be a constant presence on the airwaves and across the Central Valley in the weeks leading up to the vote. “East of I-5 is going to be Trumpland without a doubt,” he said.

But Trump also will have an incentive to come fishing for votes in the ultrablue Bay Area, where protests could dwarf the ones he faced in Chicago and across the Midwest last week.

“I would be very disappointed in California if that fascist could show up here and not have major push-back, particularly in the Bay Area,” said Cat Brooks, a leader in the Black Lives Matter movement.

While protesters are likely to start preparing for Trump’s arrival, some of his independent-minded fans are already registering as Republicans so they can vote for him, said Harmeet Dhillon of San Francisco, the state vice chairwoman.

She sees Trump and Cruz faring well in the state, but sees few prospects for Kasich, who — already mathematically eliminated in the delegate count — is hoping to win the nomination at the convention.

“A brokered convention is anathema to many people even if they don’t like Trump,” Dhillon said.

But, she added, a hotly contested GOP primary is good news for the state party, especially for Republicans candidate in local races.

“I love it,” she said. “We are very relevant to the national party from a donor point of view, but (otherwise) we’ve been kind of the ugly stepchild. … So I’m excited to see our state be relevant again.”

Contact Matthew Artz at 510-208-6435. Follow him on Twitter at Matthew_Artz.