WASHINGTON (AP) — JD Vance not long ago described conspiracy theories as the feverish imaginings produced by "fringe lunatics writing about all manner of idiocy."

That was before he became a rising star in Republican politics.

The Ohio senator and GOP's vice presidential nominee has in recent years declared that the federal government deliberately allowed fentanyl into the United States to kill conservative and rural voters. He has praised Alex Jones, a well-known conspiracy theorist who claimed the deaths of 20 young children in the 2012 Sandy Hook school shooting was a hoax.

And he's echoed — contrary to all evidence — former President Donald Trump's assertion that the 2020 election was unfairly won by Democrats and that those charged in the subsequent Capitol insurrection are "political prisoners." More recently, he gave credence to the debunked idea that Haitian immigrants were abducting and devouring pets in Ohio.

Longtime Republican strategists and academics say Vance's evolution on the conspiracy theories can be traced to the Ohio politician's desire to advance in Trump's Republican Party. The former president has a long history of pushing unfounded claims. He lied about former President Barack Obama having been born in Kenya, and about doctors performing "post-birth abortions." He has said that wind turbines cause cancer. And he has repeatedly amplified social media posts that elections cannot be trusted.

Reinvented himself

Vance has "entirely reinvented himself," said Joseph Uscinski, a University of Miami professor and expert on the history of conspiracy theories. "It's advantageous now because of what Trump has done to the GOP. It probably would not have worked, you know, 20, 30 years ago. He would have been seen as a kook. But now given what Trump has done to the GOP, this is sort of par for the course."

Denying conspiracy theories is not a recipe for electoral success.

Mike Pence and Liz Cheney are examples of what can happen to those who refuse to embrace such ideas. Pence, Trump's former vice president, refused to go along with the scheme to overturn the 2020 election, ensuring his run in the 2024 GOP presidential primary went nowhere. Former Rep. Cheney came under assault from Trump and his allies after she helped lead the House investigation into his role in the insurrection. She was stripped of her leadership role in Congress and lost her House seat to a Trump-endorsed candidate in the Republican primary.

A spokesperson for Vance's campaign said that while the candidate stands by many of his claims — including the idea that immigrants in Ohio are abducting pets — others have been misrepresented by Democrats.

Vance suggested recently that he is comfortable sharing unfounded claims if they draw attention to an issue.

"If I have to create stories so that the American media actually pays attention to the suffering of the American people, then that's what I'm going to do," he said Sunday on CNN.

Later in the same interview he said his claims about abducted pets had helped to "focus" the media's attention on immigration.

From intellectual to conspiracy theorist

Vance, 40, found early success and fame as the writer of "Hillbilly Elegy," his best-selling 2016 memoir that examined the plight of rural America.

Besides labeling conspiracy theorists as "fringe lunatics" in the book, Vance wrote that their beliefs were popular, in part, because people had lost faith in the media. "With little trust in the press, there's no check on the Internet conspiracy theories that rule the digital world."

Before he wrote the book, Vance expressed similar insights to friends.

Cullen Tiernan served in the U.S. Marines with Vance when they were deployed to Iraq in 2005 and 2006. Tiernan said Vance routinely rejected conspiracy theories that came up in discussions, including one that alleged the U.S. government had actually been behind the Sept. 11, 2001, attack.

Vance "just didn't have time for it," said Tiernan, who remains a close friend of the senator.

A review of Vance's published works and speeches shows he first began diving into the conspiracy pool after announcing his candidacy in 2021 for an open U.S. Senate seat in Ohio.

He defended Jones, the host of InfoWars, in a 2021 speech, saying that "believing crazy things is not the mark of whether somebody should be rejected."

A spokesperson for Vance's campaign told the AP that the candidate doesn't agree with Jones when it comes to the Sandy Hook massacre, before comparing that conspiracy theory to Democratic concerns about Russian support for Trump in 2016.

The senator has also repeatedly questioned the seriousness of the Jan. 6, 2021, insurrection and dismissed the threats on Pence's life — rioters were searching for the vice president in the Capitol, chanting, "Hang Mike Pence!"

He said the "real assault on democracy" wasn't Jan. 6 — but the fact that people charged in the riot were still locked up.

"It is an insult to all of us that so many people are rotting in prison without being offered a speedy trial. These people are political prisoners," he wrote on social media in 2022.

And he wrote a favorable blurb for a book that came out in July by Jack Posobiec, a political operative who is perhaps best known for promoting the " Pizzagate " conspiracy that alleged Democrats were pedophiles who were hiding abducted children in pizza parlors.

Echoing Great Replacement Theory

Vance has also invoked George Soros, one of the far right's favorite bogeymen.

Soros, the Jewish financier and Democratic megadonor, is such a ubiquitous target in some conservative circles that it can obscure the longstanding antisemitic tropes mirrored in language used to describe him: of rich Jewish bankers secretly controlling the world, wealthy Jewish puppet masters pulling the strings of those in power.

In December 2021, Vance said Soros " has blood on his hands " for helping Philadelphia District Attorney Larry Krasner get into office. "George Soros put millions into Krasner's campaigns, which promised to go easy on the types of criminals who commit these murders," Vance wrote on X.

Vance has promoted the "great replacement theory," which claims that Democrats are trying to use immigrants to replace white Americans in a bid to control the nation. Rooted in anti-Semitism and racism, many adherents to the theory claim the scheme is being orchestrated by powerful Jews like Soros, along with other "globalists" or "elites."

"We have an invasion in this country because very powerful people get richer and more powerful because of it," Vance said on Fox News in 2022.

"It's not bad policy," Vance added, "it's evil."

Vance's campaign rejects suggestions that he engages in anti-Semitic or anti-immigrant rhetoric. It notes the candidate has three biracial children with his wife, the daughter of immigrants from India. The campaign also says Democrats have talked about how immigration could help their party's electoral chances.

"Many leading Democrats have gleefully exclaimed, in public, that changing demographics would lead to an increase in political power for their side," the campaign said.

By attacking Soros and promoting the great replacement theory, however, Vance is flirting with dangerous rhetoric that has touched off violence in the past, said Amy Spitalnick, CEO of the Jewish Council for Public Affairs.

Not long ago, major party candidates would have rejected such theories, if only out of fear that voters would see them as racist or anti-Semitic. That is no longer the case, Spitalnick said.

"It's becoming increasingly normalized and increasingly mainstreamed," she said. "It's not accidental, and it's incredibly dangerous."