The wine flowed. Donald Trump Jr. mingled with the guests. And Peter Thiel, the tech billionaire and host of the event, had a message for the well-heeled crowd: It was time to clean house.

The fund-raiser at Mr. Thiel’s Miami Beach compound last month was for a conservative candidate challenging Representative Liz Cheney of Wyoming for a spot on the ballot in November’s midterm elections. Ms. Cheney, one of several Republicans who had voted to impeach President Donald J. Trump on charges of inciting the Jan. 6 storming of the U.S. Capitol, was the face of “the traitorous 10,” Mr. Thiel said, according to two people with knowledge of the event, who were not authorized to speak publicly. All of them had to be replaced, he declared, by conservatives loyal to the former president.

Mr. Thiel, who became known in 2016 as one of the biggest donors to Mr. Trump’s presidential campaign, has re-emerged as a key financier of the Make America Great Again movement. After sitting out the 2020 presidential race, the venture capitalist this year is backing 16 Senate and House candidates, many of whom have embraced the lie that Mr. Trump won the election.

To get these candidates into office, Mr. Thiel has given more than $20.4 million. That essentially puts him and Kenneth Griffin, the chief executive of the hedge fund Citadel, in a tie as the largest individual donors to Republican politics this election cycle, according to the nonpartisan research organization OpenSecrets.

What sets Mr. Thiel’s spending apart, though, is its focus on hard-right candidates who traffic in the conspiracy theories espoused by Mr. Trump and who cast themselves as rebels determined to overthrow the Republican establishment and even the broader American political order. These campaigns have raised millions in small-dollar donations, but Mr. Thiel’s wealth could accelerate the shift of views once considered fringe to the mainstream — while making himself a new power broker on the right.

“When you have a funder who is actively elevating candidates who are denying the legitimacy of elections, that is a direct assault on the foundation of democracy,” said Lee Drutman, a senior fellow at the left-leaning group New America, who studies campaign finance and hyperpartisanship.

The candidates Mr. Thiel has funded offer a window into his ideology. While the investor has been something of a cipher, he is currently driven by a worldview that the establishment and globalization have failed, that current immigration policy pillages the middle class and that the country must dismantle federal institutions.

Mr. Thiel has started articulating his thinking publicly, recently headlining at least six conservative and libertarian gatherings where he criticized the Chinese Communist Party and big tech companies and questioned climate science. He has taken issue with what he calls the “extreme dogmatism” within establishment institutions, which he said had sent the country backward.

At an October dinner at Stanford University for the Federalist Society, he spoke about the “deranged society” that “a completely deranged government” had created, according to a recording of the event obtained by The New York Times. The United States was on the verge of a momentous correction, he said.

“My somewhat apocalyptic, somewhat hopeful thought is that we are finally at a point where things are breaking,” Mr. Thiel said.

Mr. Thiel, 54, has not publicly said what he believes about the 2020 election. But in Mr. Trump, he sees a vessel to push through his ideological goals, three people close to the investor said. The two men met recently in New York and at the former president’s Mar-a-Lago club in Palm Beach, Fla. Mr. Thiel also funded an app company run by John McEntee, one of Mr. Trump’s closest aides, two people with knowledge of the deal said.

Unlike traditional Republican donors who have focused on their party’s winning control of Congress and the White House, Mr. Thiel has set his sights on reshaping the Republican agenda with his brand of anti-establishment contrarianism, said Stephen K. Bannon, Mr. Trump’s former chief strategist.

“I don’t think it’s just about flipping the Senate,” said Mr. Bannon, who has known Mr. Thiel since 2016. “I think Peter wants to change the direction of the country.”

Mr. Thiel’s giving is expected to make up just a small fraction of the hundreds of millions of dollars that are likely to flow through campaigns this cycle. But the amounts he is pouring into individual races and the early nature of his primary donations have put him on the radar of Republican hopefuls.

In the past, many courted the billionaire Koch brothers or Sheldon Adelson, the late casino magnate. This year, they have clamored for invitations to Mr. Thiel’s Los Angeles and Miami Beach homes, or debated how to at least get on the phone with him, political strategists said.

Mr. Thiel personally vets the candidates he gives to, said three Republican strategists, who declined to be named for fear of retaliation. In addition to Harriet Hageman, the challenger to Ms. Cheney, he is backing Joe Kent and Loren Culp, both of whom are running against House Republicans in Washington State who voted to impeach Mr. Trump. He also gave to a political action committee associated with Senator Ted Cruz, Republican of Texas, who is not up for re-election this year.

Mr. Thiel has attracted the most attention for two $10 million donations to the Senate candidates Blake Masters in Arizona and J.D. Vance in Ohio. Like Mr. Thiel, the men are tech investors with pedigrees from elite universities who cast themselves as antagonists to the establishment. They have also worked for the billionaire and been financially dependent on him. Mr. Masters, the chief operating officer of Thiel Capital, the investor’s family office, has promised to leave that job before Arizona’s August primary.

Mr. Thiel, who declined to comment for this article, announced last week that he would leave the board of Meta, the parent company of Facebook, which conservatives have accused of censorship. One reason for the change: He plans to focus more on politics.

A Moneyman’s Evolution

Born in West Germany and raised in South Africa and the San Francisco Bay Area, Mr. Thiel showed his provocative side at Stanford in the late 1980s. Classmates recalled Mr. Thiel, who studied philosophy and law, describing South Africa’s apartheid as a sound economic system. (A spokesman for Mr. Thiel has denied that he supported apartheid.)

Mr. Thiel also helped found The Stanford Review, a conservative campus paper that sought to provide “alternative views” to what he deemed left-wing orthodoxy.

In 1995, he co-wrote a book, “The Diversity Myth,” arguing that “the extreme focus on racism” had caused greater societal tension and acrimony. Rape, he and his co-author, David Sacks, wrote, sometimes included “seductions that are later regretted.” (Mr. Thiel has apologized for the book.)

In 1998, Mr. Thiel helped create what would become the digital payments company PayPal. He became Facebook’s first outside investor in 2004 and established the venture capital firm Founders Fund a year later. Forbes puts his fortune at $2.6 billion.

As a venture capitalist, Mr. Thiel branded himself as a contrarian. He published philosophical essays, often dark musings on politics, technology, Christianity and globalization.

In one 2009 piece, Mr. Thiel, who called himself a libertarian, wrote that he had come to “no longer believe that freedom and democracy are compatible,” arguing that American politics would always be hostile to free-market ideals, and that politics was about interfering with other people’s lives without their consent. Since then, he has hosted and attended events with white nationalists and alt-right figures.

His political giving evolved with those views. He donated lavishly to Ron Paul’s 2008 and 2012 presidential campaigns before turning to candidates who were more extreme than the Republican establishment.

In 2013, Curtis Yarvin, an entrepreneur who has voiced racist beliefs and said democracy was a destructive system of government, emailed Mr. Thiel. Mr. Yarvin wrote that Mr. Cruz, then a newly elected senator, “needs to purge every single traitor” from the Republican Party. In the email, which The Times obtained, Mr. Yarvin argued that it didn’t matter if those candidates lost general elections or cost the party control in Congress.

Mr. Thiel, who had donated to Mr. Cruz’s 2012 campaign, replied, “It’s relatively safe to support Cruz (for me) because he threatens the Republican establishment.”

Mr. Thiel used his money to fund other causes. In 2016, he was revealed as the secret funder of a lawsuit that targeted Gawker Media, which had reported he was gay. Gawker declared bankruptcy, partly from the costs of fighting the lawsuit.

In July 2016, Mr. Thiel appeared at the Republican National Convention to proclaim that he was proud to be a gay Republican supporting Mr. Trump. He later donated $1.25 million to the candidate.

After Mr. Trump won, Mr. Thiel was named to the president-elect’s executive transition team. At a meeting with tech leaders at Trump Tower in Manhattan in December 2016, Mr. Trump told Mr. Thiel, “You’re a very special guy.”

A month later, Mr. Thiel, a naturalized American, was revealed to have also obtained citizenship in New Zealand. That prompted a furor, especially after Mr. Trump had urged people to pledge “total allegiance to the United States.”

During Mr. Trump’s presidency, Mr. Thiel became frustrated with the administration. “There are all these ways that things have fallen short,” he told The Times in 2018.

In 2020, he stayed on the sidelines. His only notable federal election donation was to Kris Kobach, a Trump ally and former secretary of state of Kansas known for his hard-line views on immigration. (Mr. Kobach lost his primary bid for the Senate.)

Mr. Thiel’s personal priorities also changed. In 2016, he announced that he was moving from San Francisco to Los Angeles. The next year, he married a longtime boyfriend, Matt Danzeisen; they have two children.

Mr. Thiel reduced his business commitments and started pondering leaving Meta’s board, which he had joined in 2005, two of the people with knowledge of his thinking said. At an October event held by a conservative tech group in Miami, he alluded to his frustration with Facebook, which was increasingly removing certain kinds of speech and had barred Mr. Trump.

“I will take QAnon and Pizzagate conspiracy theories any day over a Ministry of Truth,” he said.

A Meta spokeswoman said the company valued and had benefited from Mr. Thiel’s contributions.

Mr. Thiel reappeared in political circles. In August, he bought a $13 million mansion in Washington from Wilbur Ross, Mr. Trump’s commerce secretary. In October, he spoke at the event for the Federalist Society at Stanford and at the National Conservatism Conference.

He also rebuilt his relationship with Mr. Trump. Since the 2020 election, they have met at least three times in New York and at Mar-a-Lago, sometimes with Mr. Masters or Mr. Vance. And Mr. Thiel invested in Mr. McEntee’s company, which is building a dating app for conservatives called the RightStuff.

Mr. McEntee declined to answer questions about his app and said Mr. Thiel was “a great guy.” Mr. Trump’s representatives did not respond to requests for comment.

Giving to Win

Mr. Thiel’s political giving ramped up last spring with his $10 million checks to PACs supporting Mr. Vance and Mr. Masters. The sums were his biggest and the largest ever one-time contributions to a PAC backing a single candidate, according to OpenSecrets.

Like Mr. Trump in 2016, Mr. Vance and Mr. Masters lack experience in politics. Mr. Vance, the venture capitalist who wrote the best-selling memoir “Hillbilly Elegy,” met Mr. Thiel a decade ago when the billionaire delivered a lecture at Yale Law School, where Mr. Vance was a student.

Mr. Vance later worked at Mithril Capital, one of Mr. Thiel’s investment funds, before opening his own fund in Ohio, Narya Capital, in which Mr. Thiel is an investor. Mr. Vance took home more than $400,000 in salary from Narya in 2020 and the first half of 2021, according to financial disclosures.

Mr. Masters met Mr. Thiel when he was a Stanford law student in 2012 and the investor taught a class on start-ups. The two later co-wrote a best-selling business book, “Zero to One.” In 2020, Mr. Masters reported more than $1.1 million in salary from Thiel Capital and book royalties.

Mr. Vance, Mr. Masters and their campaigns did not respond to requests for comment.

Both candidates have repeated the Trumpian lie of election fraud, with Mr. Masters stating in a November campaign ad, “I think Trump won in 2020.” They have also made Mr. Thiel a selling point in their campaigns.

In November, Mr. Vance wrote on Twitter that anyone who donated $10,800 to his campaign could attend a small group dinner with him and Mr. Thiel. Mr. Masters offered the same opportunity for a meal with Mr. Thiel and raised $550,000 by selling nonfungible tokens, or NFTs, of “Zero to One”digital art that would give holders “access to parties with me and Peter.”

Mr. Thiel’s backing has prompted other tech investors to support the two candidates. Mr. Sacks, the co-author of “The Diversity Myth” and now an investor, hosted a fund-raiser for Mr. Vance. Joe Lonsdale, a venture capitalist, held one for Mr. Masters.

Mr. Thiel has also made smaller donations to Trump loyalists, including in September to Ms. Hageman and Patrick Witt, a former Trump administration official running for a House seat in Georgia.

His backing may not be enough. In Ohio, Mr. Vance trails in polling, partly hampered by a previous denunciation of Mr. Trump. In Arizona, Mr. Masters is competing in a crowded field.

Still, some Republicans worry that Mr. Thiel is arming candidates who are too extreme with financial firepower, fueling what could be politically detrimental primary races.

“You have to nominate candidates who can win in the fall and not just damage everyone on the way,” said Scott Reed, a longtime Republican strategist.

But Mr. Thiel appears ready to press forward. In a 20-minute speech at the National Conservatism Conference in October, he said nationalism was “a corrective” to the “brain-dead, one-world state” of globalism. He also blasted the Biden administration.

“We have the zombie retreads just busy rearranging the deck chairs,” he said. “We need dissident voices more than ever.”

Cade Metz contributed reporting. Rachel Shorey and Kitty Bennett contributed research.