Biden faces new setbacks in fight to stay on presidential ticket

The new developments showed that the efforts to oust Biden, while quieter in the immediate aftermath of an assassination attempt on Donald Trump, haven’t stopped. They reveal how the president’s grip on his party has slipped, with his top lieutenants bending after a threatened revolt over the campaign’s effort to speed his nomination.

The Democratic maneuvering comes as the Republican Party is roundly unifying around Trump at its convention in Milwaukee. The former president, already popular with the GOP base, has garnered near-mythic status among supporters after shots were fired at him during a rally in Butler, Pa., on Saturday. Some convention-goers are even wearing white rectangle-shaped bandages over their right ear to show solidarity with Trump, who was nicked by a bullet.

It presents a jarring contrast: An energized and unified Republican party eager to anoint their chosen candidate while the Democratic Party is mulling an end-run around their normal process to install an 81-year-old leader who has an exceedingly narrow path to victory, threatens to be a drag on down-ballot races, and has done little to reassure key Democrats about his ability to effectively campaign over the next four months.

The defection of Schiff, a prominent antagonist of Trump and a close ally of former House Speaker Nancy Pelosi (D., Calif.), stands out because he’s one of the highest-profile Democrats to make such a call. He is currently running for Senate and is favored to win in November.

“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," he said in a statement. Schiff also said that “while the choice to withdraw from the campaign is President Biden’s alone, I believe it is time for him to pass the torch." He is the 19th House Democrat to say Biden should leave the race, along with one Democratic senator.

Biden’s allies initially sought votes Friday and Sunday to set the groundwork for an online balloting effort to install the president as their 2024 nominee. They used the rationale that a deadline to include Biden on the Ohio ballot necessitated the change.

The accelerated timeline prompted outrage from rank-and-file lawmakers and party donors who pointed out that Ohio had changed its rules since the idea of a virtual nomination was first set in motion in May, making the deadline moot.

Senate Majority Leader Chuck Schumer (D., N.Y.), in consultation with House Minority Leader Hakeem Jeffries (D., N.Y.) pushed for Democratic officials to delay the first steps in preparing for the virtual nomination vote, according to people familiar with the matter. Under the current plan, online voting would begin as early as Aug. 1. Party officials are aiming to wrap up Biden’s formal nomination by Aug. 7—nearly two weeks before the start of the Democratic National Convention in Chicago and ahead of the one-time Ohio deadline.

There is little doubt, even with Democratic defections, that Biden has more than enough support among the delegates to become the party’s nominee on the first ballot. But doing an online ballot ahead of the convention reduces the possibility of messy defections on the floor, which could further highlight disarray in the party. Some Biden allies believe that once the president has the nomination in hand, the efforts to remove him will end.

“I understand why, for the sake of avoiding disruption at the convention, they might want to advance the balloting," said David Axelrod, a Democratic strategist who was one of Barack Obama’s top political aides. “But under the circumstances, the effect may be to accelerate expressions of doubt and concern rather than quiet them. It’s a power play which could very well backfire."

A new poll from the AP-NORC Center for Public Affairs Research estimates that 65% of Democrats think Biden should drop out of the race.

The White House has struggled to reassure party leaders about Biden’s candidacy since his disastrous showing at the June 27 debate, when he faltered on stage and raised concerns about his mental acuity.

For example, in recent video calls with lawmakers, Biden often looked down, appearing to read from notes. Lawmakers said his performance did little to alleviate concerns that the White House needs to script his every move, one aide said. Another lawmaker on a recent call with Biden said he toggled between speaking smoothly and then, at other times, having the same difficulty completing thoughts that he displayed on the debate stage.

During a speech Tuesday in Las Vegas, the president also spoke haltingly. He inaccurately described his new housing policy as capping rent increases by $55 as he appeared to struggle to read from a teleprompter. Biden has a new housing policy that caps rent increases at 5% in some instances. He cut himself off at times by using the phrase “anyway."

Biden also shared a joke attributed to President Harry S. Truman, who said that anyone who wants a friend in Washington should get a dog. “After the last couple of weeks, I know what he means," Biden said, to laughter from the crowd.

The quip underscored his increasing isolation, with an already insular set of advisers further contracting amid the crisis. Steve Ricchetti, counselor to the president with deep ties on Capitol Hill, and adviser Mike Donilon, form the inner nucleus of staff he will listen to, according to people in touch with the White House. Lawmakers are concerned that they don’t know who to go to with their concerns about Biden.

On Tuesday, Biden in an interview with BET offered a new hypothetical rationale that could persuade him to leave the race. Asked what might prompt him to step aside, he said, “If a doctor came to me and said, ‘you got this problem, you got that problem.’" He added, “There is more to do, and I am reluctant to walk away from that."

The Democratic Party’s effort to accelerate balloting drew backlash from Democratic lawmakers, with Rep. Jared Huffman of California circulating a letter earlier this week asking the party to reconsider. Huffman withdrew his letter Wednesday after Democratic officials slowed the process for installing Biden at the top of the ticket.

Biden has said is unconcerned about a revolt during the convention, noting during his NATO news conference earlier this month that his delegates are “free to do whatever they want" at the party gathering.

But he also voiced doubt that there would be another nominee. “It’s not going to happen," Biden said in a whisper.

Rebecca Ballhaus, Emily Glazer and Ken Thomas contributed to this article.

Write to Annie Linskey at annie.linskey@wsj.com and Lindsay Wise at lindsay.wise@wsj.com