Republicans have been featuring Vice President Kamala Harris prominently in their attacks on the Biden administration at this week’s convention in Milwaukee — a sign that they believe President Biden could still step aside and elevate her to the top of the ticket.

But the movement among Democrats to persuade Biden to drop out of the race has gone quiet, in large part because of the attention former President Trump has received in the aftermath of Saturday’s attempt on his life.

“You’re not hearing anything,” said Mary Anne Marsh, a Democratic strategist. “That tells you everything.”

Democrats who believe Biden, 81, is too weak politically to run against Trump or may not be able to complete a second term remain active behind the scenes. But the shift in public momentum that some expected to emerge on Sunday and Monday of this week was waylaid by the assassination attempt — which caused a pause in political activity — and the announcement on Monday that Ohio Sen. J.D. Vance would be Trump’s running mate creating another distraction that kept public focus on Trump.

The timing is crucial because Biden is trying to run out the clock, making it harder for another nominee to take his place. Democrats appear to be moving forward with a plan to formally renominate the president by the end of the month through a virtual process, ahead of the Democratic National Convention on Aug. 19. Several Democratic lawmakers are urging the party to wait for the convention to allow more time.

Biden is in Las Vegas, where his events Tuesday include a speech at the NAACP’s national convention. He gave a nationally televised interview Monday, when he again insisted he would not entertain leaving the race, a decision that is entirely his to make.

“I call it fantasy football,” said Donna Brazile, a former chair of the Democratic Party who remains influential. “Joe Biden ain’t going nowhere.”

Republicans are not taking chances during their convention, which runs through Thursday night. Many of the speeches during Monday’s opening night included Harris — some mispronouncing her first name as Ka-MAL-a — as Biden’s governing partner. A video, for example, attacked “Biden and Harris’ open border disaster.” Sen. Marsha Blackburn, a Tennessee Republican, blamed “Joe and Kamala, bless their hearts,” for high gas prices, plans to tax small business owners and increased IRS enforcement.

“Their regulations aren’t just burdensome. Often, they include racist DEI requirements,” she said, referring to diversity, equity and inclusion hiring programs, a popular target on the right.

The attacks against Harris as a powerful governing partner to Biden carry a hint of irony because Republicans have long argued that she has been ineffective as Biden’s understudy and often excluded from making decisions, impressions that have stuck with many activists and voters.

“I don’t think she has the gravitas,” said Nancy DeLuna, a longtime GOP delegate from Palm Desert. “She is not capable of running the government and I don’t believe she has the confidence even of her own party.”

Sen. Marsha Blackburn (R-Tenn.) speaks Monday night at the Republican National Convention.

(Matt Rourke / Associated Press)

Democratic arguments around Harris as a possible replacement — and whether there was a way to open the field of possible successors — had been fairly public for more than two weeks, since Biden’s disastrous debate with Trump in which he showed signs of decline. About 20 Democratic lawmakers had called on Biden to step aside as of last Friday. But there were no new calls over the weekend, and public discussion all but shut down after Saturday’s shooting at a Pennsylvania rally that injured Trump’s ear and left one member of the audience dead in addition to the shooter. Two others were also injured.

An advisor to one Democratic lawmaker who had publicly urged Biden to step aside said Tuesday that his boss was no longer doing media appearances, while insisting “the efforts are ongoing.” Several Democrats said it would be crass to have that debate in public, in part because Biden needed to show the country that he was eager to help turn down the political rhetoric and address the security failure that allowed the gunman, Thomas Matthew Crooks, to commit the attack.

Democratic National Convention delegates voted in June, before the debate, to hold a virtual vote ahead of the convention to meet a ballot deadline in Ohio that has since been moved back. The rules committee, a powerful group of party insiders, will decide Friday when to hold the virtual vote, which would likely take place within the next two weeks.

But Democratic lawmakers are circulating a letter urging the party to wait.

“Proceeding with the ‘virtual roll call’ in the absence of a valid legal rationale will be rightly perceived as a purely political maneuver, which we believe would be counterproductive and undermine party unity and cohesion,” said the letter, which was obtained by The Times. It had not yet been sent as of Tuesday morning.

Jamal Simmons, former communications director for Harris, credited Biden’s more aggressive public schedule since the debate for assuring some detractors and demonstrating he “is the best person to be president today.” But he added that the movement to urge him to leave the race has only been on pause, even if that pause has helped Biden.

“There are still questions about whether he is the best person to run for president for the next four years, but there are fewer people asking that question today than a week ago,” he said.

Polls continue to worry many Democrats, including a YouGov poll released Monday that showed Trump leading by 2 to 7 percentage points in seven swing states, including Arizona, where he was up by 7 points.

Biden appeared dismissive during his Monday interview with NBC anchor Lester Holt, insisting “it’s essentially a toss-up race” while listing his first-term accomplishments. Holt concluded his interview by asking Biden what would happen if he had another episode like his debate performance. Biden answered inaudibly at first.

“I don’t plan on having another performance on that level,” he said finally.

Times staff writer Seema Mehta in Milwaukee contributed to this report.