Even by a conspiracy theorist’s standards, the wild claims made by Representative Clay Higgins, Republican of Louisiana, stand out.

The hard-right congressman, now in his fourth term in the House, has said that “ghost buses” took agent provocateurs to the Capitol on Jan. 6, 2021, to instigate the riot. He has claimed that the federal government is waging a “civil war” against Texas. And he has called the criminal charges against former President Donald J. Trump for mishandling classified documents a “perimeter probe from the oppressors.”

But far from relegating Mr. Higgins to the fringe of their increasingly fractious conference, House Republicans have elevated him. They made him the chairman of the subcommittee overseeing border enforcement, and Speaker Mike Johnson named him one of 11 impeachment managers tasked with trying to remove the homeland security secretary from office in a Senate trial set to take place next week.

None of it has dampened Mr. Higgins’s penchant for spreading unsupported theories, many of which portray law enforcement and the government in an evil, conspiratorial light.

This week, in a lengthy podcast interview, he expounded at length on his belief — based, he said, on his own extensive investigation and evidence that only he has been able to see — that federal law enforcement officers entrapped Mr. Trump’s supporters into violently attacking the Capitol on Jan. 6. He was repeating a conspiracy theory that has been debunked repeatedly.

Over the course of a two-hour interview on the “Implicit Bias” podcast, Mr. Higgins, wearing a shirt emblazoned with the logo of the Three Percenters, a right-wing antigovernment militia, repeated the lie that the 2020 election was fraudulent. He laid out an outlandish story that tied the rise of the coronavirus pandemic to what he said was a plot by the government to infiltrate pro-Trump online forums and urge members to engage in “riotous” behavior, as he put it.