NASHVILLE — As religious conservatives gathered this week at a sprawling resort near the Grand Ole Opry House, the former South Carolina governor who was ambassador to the United Nations under President Trump, Nikki Haley, pressed the Faith and Freedom Coalition’s “Road to Majority” crowd to look to the future.

“It’s up to us to deliver a new birth of patriotism,” said Ms. Haley, “And together with you, and with trust in God, I pledge to answer that call and inspire our country once again.”

Such comments are typical of a party that’s out of power and in search of its next leader. But what’s unusual: The party’s last leader is plotting his own comeback.

Mr. Trump is showing up on the same stage Friday, his first public appearance since the House committee investigating the January 6 attack began to lay bare his desperate attempts to remain in power by challenging American democracy. Yet, at least for now, the harrowing footage and searing testimony in the panel’s hearings, including accounts from Mr. Trump’s close associates and members of his family, appear to have done little to dampen his interest in another campaign.

Indeed, Mr. Trump is actively weighing when he might formally launch a third presidential run, according to people familiar with the discussions. The debate, according to aides and allies who insist Mr. Trump has yet to make a final decision, centers on whether to announce a campaign in the coming months or, in accordance with tradition, wait until after the November midterm elections.

Mr. Trump has spent the past year and a half holding rallies, delivering speeches and using his endorsements to exact revenge and further shape the party in his image. But some say the former president, who has decamped to Bedminster, New Jersey from his Florida Mar-a-Lago club for the summer, is also growing impatient.

While he has relished his role as a party kingmaker — with candidates all but begging his endorsement and racking up large tabs at fundraisers in his ballrooms — Mr. Trump also misses the days when he was actually king, particularly as he watches President Biden struggling with low approval ratings and soaring inflation.

“I think a lot of Trump’s future plans are directly based on Biden, and I think the more Biden continues to stumble on the world stage and on the domestic stage, people forget about the downside, the dark side of Trump’s presidency,” said a GOP strategist and former Trump campaign official, Bryan Lanza.

An announcement in the near future could complicate efforts by other ambitious Republicans to mount campaigns. Ms. Haley, for instance, has said she wouldn’t run against Mr. Trump.

But there also are concerns that a near-term announcement could hurt Republicans going into the final stretch of a midterm congressional campaign that appears increasingly favorable to the party. A Trump candidacy could unite otherwise despondent Democratic voters, reviving the energy that lifted the party in the 2018 and 2020 campaigns.

And, regardless of his decision, the aura of inevitability that Mr. Trump sought to create from the moment he left the White House has been punctured. Some Republicans and their aides have tried to make clear in recent months that a Trump candidacy would have little influence on their own decisions.

They include Mr. Trump’s running mate, Vice President Pence, who has been hailed by the January 6 committee as someone who put the national interest ahead of his own political considerations. Eyeing a White House bid, Mr. Pence is maintaining a brisk political schedule focused on drawing attention to Democratic vulnerabilities.

Others, including Senator Cruz and the former New Jersey governor, Chris Christie, have also indicated their decisions do not rest on Mr. Trump’s. And they and others have become increasingly brazen in their willingness to cross the former president, including endorsing candidates running against his and even campaigning with Georgia’s Republican governor, Brian Kemp, who survived Mr. Trump’s efforts to defeat him in the state’s GOP primary last month.

Some of these could-be candidates, including Mr. Trump’s Secretary of State, Mike Pompeo, Senator Scott of Florida and Senator Scott of South Carolina, were appearing alongside the former president as he headlines the Faith and Freedom Coalition’s gathering in Nashville.

The field could include a long list of others, including Representative Elizabeth Cheney, the lead Republican on the January 6 panel and Maryland’s governor, Larry Hogan — both Trump critics. Governor DeSantis of Florida, meanwhile, is seen by many loyal Trump supporters as the future of his movement.

Indeed, many of those attending the conference in Nashville — the resort is near the Opry House, where the longtime “Grand Ole Opry” country music radio show is broadcast — weren’t sold on a third Trump run.

“I don’t know. The jury’s still out with me,” said a minister, Jonathan Goodwin, who works as a Faith and Freedom organizer in South Carolina. “I like him, but I think he shot himself in the foot too many times”

While Mr. Goodwin said he “definitely” had his own concerns about the 2020 election, he said he didn’t support how Mr. Trump had handled the situation. “I think he should have bowed out gracefully,” he said, “whether it was rigged or not.”

Illinois conservative Pam Roehl, who arrived at the conference Friday wearing a red Trump baseball cap and “Trump 2020” necklace, said she still supports the former president, but was increasingly finding herself in the minority among like-minded friends, whom she said had moved on, discarding their bumper stickers, and embracing Mr. DeSantis.

“They’re like kind of, ‘Get with the program. Why aren’t you backing DeSantis?’” she said.

Though it’s increasingly clear that Mr. Trump wouldn’t march to the GOP nomination unchallenged, a large field of candidates could still work to his advantage. The dynamic is beginning to resemble the 2016 campaign, when Mr. Trump faced a large and unwieldy group of candidates that split the anti-Trump vote.

In a crowded field, even if Mr. Trump only captures around 30 percent of GOP primary voters — as his endorsed candidates have in several races — he would sail to the Republican nomination.

Aides say Mr. Trump has been peppering those around him for their thoughts.

Some in his orbit, like former campaign adviser Jason Miller, have urged Mr. Trump to jump in sooner rather than later, to get a head start on building out a campaign, try to freeze out competition and keep attention on himself.

An early strategy would also allow Mr. Trump to cast his mounting legal vulnerabilities as merely political attacks. An Atlanta district attorney has impaneled a special grand jury to probe his meddling in the 2020 presidential election. And in New York, Mr. Trump and two of his children have agreed to sit for depositions next month in the state attorney general’s civil investigation into his business practices.

Others are urging Mr. Trump to wait until after the midterms, so he can run on Republicans’ November victories. They note that his frequent teasing of his plans — Mr. Trump often muses he’ll “do it again” — earns him applause and media attention and warn that formally declaring his candidacy would trigger campaign finance laws that set limits on how much donors can give. 

It also would change his relationship with his Save America PAC, which has more than $100 million in the bank — more than both national party organizations combined — and currently funds his campaign travel.

Either way, many voters say, he will need to win them over.

Jake Thomson, 19, who goes to school in Alabama and will be a first-time presidential voter in 2024, said he thought Mr. Trump was a great president, but was also interested in alternatives.

“It just kind of depends on how things play out,” he said.