Rep. Adam B. Schiff has called on President Biden to drop out of the White House race, becoming the most prominent Democrat in Congress to do so.

The announcement Wednesday from Schiff — the heavy favorite in his U.S. Senate bid and a frequent guest on cable news — brought a jolt to an effort that had grown quiet after the weekend assassination attempt on former President Trump.

The Burbank congressman cited “serious concerns” about Biden’s ability to beat Trump in November.

He is the latest Democrat to call for the president of his own party to exit the race amid growing questions about Biden’s age and mental fitness to do the job — worries that began in earnest after last month’s disastrous debate performance, in which the incumbent at times appeared confused.

In a statement reported first by The Times, Schiff said Biden “has been one of the most consequential presidents in our nation’s history, and his lifetime of service as a Senator, a Vice President, and now as President has made our country better.”

“But our nation is at a crossroads,” he said. “A second Trump presidency will undermine the very foundation of our democracy, and I have serious concerns about whether the President can defeat Donald Trump in November.”

Schiff said the “choice to withdraw from the campaign is President Biden’s alone,” but that he believes it is time for Biden, who tested positive Wednesday for COVID-19, “to pass the torch” and “secure his legacy of leadership” by allowing another Democrat to beat Trump.

The congressman also said he will fully support whoever ends up at the top of the Democratic ticket.

“I will do everything I can to help them succeed,” Schiff said. “There is only one singular goal: defeating Donald Trump. The stakes are just too high.”

Before his announcement, the Washington Post had tallied 22 other Democrats in Congress asking Biden to drop out. Schiff is a notable addition to the list.

He is considered close with Rep. Nancy Pelosi (D-San Francisco), a party leader whose position on Biden has been guarded — though she suggested at one point that the president was running out of time to decide whether to leave the race.

When she was speaker, Pelosi used her authority to appoint Schiff to lead the House Intelligence Committee, which is among the most important posts in Congress. She later appointed him to lead the first impeachment against Trump, one of the highest stakes decisions in her career — and one that helped Schiff rise to national prominence.

When he decided to run for Senate, she endorsed him against two progressive women.

A source close to Pelosi, who requested anonymity to speak candidly about her communications on the matter, said Schiff’s announcement “came as news to her” and that Schiff “did not consult her” on it beforehand.

Biden has dismissed the calls to step aside. He has said he has a strong record in the Oval Office and that “average Democrats” want him to remain in the race even if “big names” do not. He has tried to run out the clock on those critics and withstand their pressure long enough to make finding a replacement for him logistically difficult, if not impossible.

“I’m all in,” he told a cheering crowd at the NAACP national convention in Las Vegas on Tuesday.

Biden has also suggested that those voicing concerns about his candidacy may be more concerned about their own chances of winning in down-ballot races.

“The truth of the matter is, I understand the self-interest of a candidate. If they think that, you know, running with Biden at the top of the ticket is going to hurt them, then they’re going to run away,” he said at a news conference Thursday.

Schiff is expected to win a Senate seat that was long held by the late Sen. Dianne Feinstein, a Democrat, and is currently held by Sen. Laphonza Butler, whom Gov. Gavin Newsom appointed to serve out the remainder of Feinstein’s term after her death in September. Schiff faces retired Dodgers All-Star Steve Garvey, a Republican, after beating other leading Democratic contenders in a crowded primary this year.

After Trump was shot at a campaign rally in Pennsylvania on Saturday, the pace and volume of calls for Biden to get out of the race fell, leading some political observers to wonder if the shooting would tamp down such calls for good. Schiff’s announcement — delivered in the middle of a Republican National Convention, where Republicans have appeared extremely unified and where Trump’s former rivals in the party have lined up behind him — shows that is not the case.

Schiff’s decision also came the day an Associated Press poll showed that nearly two-thirds of Democrats believe Biden should withdraw.

A polling memo by the Democratic firm BlueLabs Analytics, first published by Politico, found that alternative candidates perform 3 percentage points better than Biden in a theoretical matchup with Trump in battleground states.

Though Vice President Kamala Harris was among those who tested better than Biden, she performed worse than several other would-be replacements, including Arizona Sen. Mark Kelly, Maryland Gov. Wes Moore, Pennsylvania Gov. Josh Shapiro and Michigan Gov. Gretchen Whitmer.

But Harris would have advantages if Biden were to drop out. She would have the easiest access to the campaign’s infrastructure, including its fundraising account. And she was on the ticket with Biden when he was elected in 2020 and in office when he became the presumed nominee this year.

Harris has many backers if Biden withdraws, including Rep. James E. Clyburn, an influential South Carolina Democrat with deep ties to Biden.

But many Democrats have been pushing for a new process that would allow alternatives, often citing Harris’ poor poll numbers.

“We have a deep bench,” Rep. Scott Peters, a San Diego Democrat who has argued Biden should drop out, said in a recent interview with The Times. “I would love to hear from a lot of folks about their perspectives. I think that it could be exciting and could get a lot of attention if we paraded out all the amazing leaders we have who are governors, senators, many elected from the swing states themselves.”

Asked why he did not mention Harris, Peters said she was one of the people he was referring to.

“She’s got a strong case and is very talented,” he added. “But we have to be really focused on who can win.”

Newsom also has been floated as a potential candidate. But the governor, a Biden surrogate, has said he has no intention of running and would not run against Harris.

Biden has been dismissive of polls, calling them inaccurate and misleading. “I can give you a series of polls where you have likely voters, me versus Trump, where I win all the time,” he said.

Democrats are planning to hold a virtual vote before the Aug. 19 convention in Chicago, perhaps this month. But some members of Congress are pushing back, circulating a letter urging the party to wait.

Peters said Biden “is being protected” from bad news by his advisors if he’s not seeing polls that show he can’t win, “because that’s what the polling shows.”

The New York Times reported Tuesday that Schiff had warned attendees at a Democratic fundraiser on Saturday that the party would lose the Senate and miss out on a chance to take the House if Biden didn’t drop out.

Schiff’s statement further increases the pressure on Biden and could prompt other lawmakers who have private concerns to come out publicly.