As more Democrats call for President Biden to step aside before the Democratic National Convention, the 81-year-old president has responded with a clear message: I’m not going anywhere.

“I beat him once, and I will beat him again,” Biden said of President Trump during a news conference last week in Washington. And on MSNBC’s “Morning Joe,” the president told his skeptics: “Run against me. Go ahead. Announce for president. Challenge me at the convention.”

Biden’s grip on the Democratic Party nomination is ironclad, if he wants it, experts say. But if Biden stepped aside before the DNC in mid-August, opening the floor to a contested convention, California’s 496-person delegation — the largest in the country — would play a pivotal role.

Dan Schnur, a politics professor at USC, UC Berkeley and Pepperdine, said the sheer size of the delegation ensures California would have an “undue amount of influence” in selecting Biden’s replacement. The Golden State delegates also hail from one of the country’s most liberal states, meaning the delegation could “lean further left than might be the case for delegations from a lot of swing states,” Schnur said.

“A very large and very progressive group of California Democrats could have an immense impact on the selection of the nominee,” Schnur said.

How do California’s delegates feel?

Two members of California’s congressional delegation have publicly called on Biden to abandon his reelection bid.

Rep. Mike Levin (D-San Diego), who is in a reelection fight in the 49th Congressional District, said Friday that “the time has come for President Biden to pass the torch.” Levin said the party has to prioritize the “incalculable threat Donald Trump poses to the American institutions of freedom and democracy.”

Scott Peters, a fellow Democratic congressman from San Diego, on Thursday expressed alarm about polls showing Biden’s dwindling support in crucial swing states.

“The stakes are high, and we are on a losing course,” Peters said in a statement. “My conscience requires me to speak up and put loyalty to the country and to democracy ahead of my great affection for, and loyalty to, the president and those around him.”

Rep. Mark Takano (D-Riverside) was one of four members who, during a private call with other senior House Democrats earlier this month, said Biden should withdraw from the race. His office declined an interview request.

How the DNC works

To win the Democratic Party nomination, a presidential candidate must secure more than half of the party’s 3,939 delegates. Biden has already won about 99% through the state primaries.

The DNC has not released a full list of delegates, but some state parties — including those in Wisconsin, Massachusetts, Florida and Ohio — have published the names of their delegates on their websites.

California’s Democratic Party has published the names of the state’s 277 elected delegates, but not the full delegation list. The 42 Democrats in Congress each have a spot, as does Gov. Gavin Newsom.

Christian Grose, a professor of political science and public policy at USC, said that California’s delegates are powerful not only because of the group’s overall size but because the DNC has reduced the number of automatic delegates. Those officials don’t vote in the first ballot, meaning the elected delegates from each state hold most of the power.

Anyone hoping to shift delegates away from Biden, he said, “would really have to move the California delegation.”

California also has 55 “automatic delegates” — previously called super delegates — drawn from a pool of statewide elected officials, labor leaders and big-city mayors. All of the state’s top Democrats are delegates, including Lt. Gov. Eleni Kounalakis, Atty. Gen. Rob Bonta, Secretary of State Shirley Weber and California Supt. of Public Instruction Tony Thurmond, according to a copy of the list shared with The Times by the state Democratic Party.

Los Angeles Mayor Karen Bass, San Francisco Mayor London Breed and San Diego Mayor Todd Gloria are included, as are Lorena Gonzalez Fletcher, the head of the California Labor Federation; civil rights activist Dolores Huerta; and the heads of local and statewide unions representing firefighters, utility workers, teachers and construction workers.

The list also includes Yvette Martinez, the executive director of the California Democratic Party; Mark Gonzalez, the former head of the L.A. County Democratic Party; and Mona Pasquil Rogers, who worked in the administrations of Newsom and former Gov. Jerry Brown and is now the head of California public policy for Meta.

Do Democratic delegates have to vote for Biden?

Biden said last week that delegates are “free to do whatever they want” at the upcoming convention, including nominate another candidate. Then he said, in a mock whisper: “It’s not going to happen.”

“Barring another performance like the debate, if Biden wants to be the nominee, he’s going to be the nominee,” Schnur said.

That tracks with members of California’s convention delegation, many of whom have said that a contested convention or a floor fight seems very unlikely. The vast majority of convention delegates, who were vetted and approved by the Biden campaign, wouldn’t switch horses without Biden’s permission.

There is “a world where that isn’t the case,” Gloria said, “but I really don’t see that happening.”

Rep. Brad Sherman (D-Porter Ranch) said that he is carefully watching Biden’s public appearances, but that his nomination is most likely “a foregone conclusion.” And Rep. Robert Garcia (D-Long Beach), who is a Biden surrogate, said that “by the time our convention rolls around, this party will be unified.”

Still, “there is no pain-free way to have a nominee,” Sherman said. “The most pain-free way is to go with Biden — and that’s still painful because we’ve gone through two weeks of self-flagellation and wondering.”

California law requires that convention delegates cast their votes on the first ballot based on who won the primaries. Sherman, who has not called on Biden to step aside, said he thinks that law is unconstitutional.

He cited a 2016 federal court case in which a Virginia delegate to the Republican National Convention filed a lawsuit seeking to overturn a law that required delegates to vote on the first convention ballot for the winner of the primary election. Violating the law was a misdemeanor offense. The delegate argued in court that he could vote his conscience on the first ballot. A federal judge sided with him and tossed out Virginia’s law.

Overturning California’s law would probably require a similar lawsuit, experts said. Whether that would matter at the convention is another question.

National conventions aren’t bound by state laws, and can set their own rules. This year, the DNC’s rules state that: “Delegates elected to the national convention pledged to a presidential candidate shall in all good conscience reflect the sentiments of those who elected them.”

Voters who cast their ballots in the primary wanted the version of Biden that “we saw for three years and three months,” Sherman said, and not the off-his-game Biden who appeared at the June 27 debate. The question for delegates, he said, is how they would reflect that desire on the convention floor.

“Nobody voted for June 27 Joe,” Sherman said. “That’s not even a Joe that Joe Biden likes.”