The Arizona Republican congressman Paul Gosar had a simple message for the crowd when he recently addressed a packed Donald Trump rally in his home state – a gathering that had focused on promoting the baseless lie that Trump had been cheated out of a second term as president.

“This is where it all began,” Gosar said in a speech before Trump came on stage. “This is where we questioned: ‘Was there fraud? Absolutely. Was it enough to overturn the election? Absolutely.’”

The far-right congressman is one of Trump’s most loyal backers in Congress, earning him one of more than 90 endorsements made so far by the former US president ahead of this year’s crucial midterm elections. Gosar is the kind of politician that Trump – who is embarking on a series of rallies to try to cement his allies’ power in the Republican party – is increasingly seeking to support.

But Gosar has extensive links to white nationalists and Capitol rioters and, many observers say, represents a dangerous new breed of Republican politician, who would have once been considered fringe, but whom Trump is increasingly making central to Republican party politics.

“I’m considered the most dangerous man in Congress,” Gosar told the crowd, briefly touching on popular rightwing talking points – critical race theory in schools, disrespect for the military, and “empty shelves” in stores – before focusing on the central theme of the rally: elections.

In the Arizona desert the fervor among supporters huddled against the wind was a clear sign of the size of a constituency more loyal to Trump than to the party, and even as some lawmakers distance themselves from the former president amid the January 6 fallout, the far right is doubling down.

In his first public appearance since the anniversary of the January 6 attack, Trump’s appearance was marked with a reaffirmation of election denial, conspiracy theories and anti-democratic ruminations. “I ran twice, and I won twice,” Trump told his supporters gathered in the windy Arizona night.

At the rally the “Stop the Steal” organizer Ali Alexander moved through the crowd while on stage three members of Congress, who all voted against certifying Joe Biden’s 2020 presidential election victory, gave speeches affirming their support of the “big lie”.

Gosar’s allegiance to Trump and his false claims extends beyond speaking the shibboleth of the big lie: on January 6 Gosar voted against certifying the election even as rioters penetrated the Capitol.

“We no longer have an ability to make a clear delineation between the right and far-right in the Republican party,” said Joe Lowndes, professor of political science at the University of Oregon and co-author of Producers, Parasites, Patriots: Race and the New Right-Wing Politics of Precarity.

“The Trumpist wing of the Republicans isn’t just ascending – it’s the dominant wing of the Republican party. It’s the dominant wing not just in national politics, but in state and local politics as well,” said Lowndes. “The Republican party has committed itself to a party of minoritarian rule, figuring out ways to rule in the long term without having majority support of voters.”

Gosar’s involvement with the January 6 Capitol insurrection has come under scrutiny from lawmakers. A House select committee investigating the deadly Capitol attack has been working for six months, in meetings mostly closed to the public, interviewing more than 300 witnesses and collecting more than 35,000 pages of records, according the Washington Post.

Information has surfaced that link Gosar to one prominent Capitol riot organizer.

A lawsuit filed by Alexander to block the release of his phone records, subpoenaed by the House committee, reveals testimony that discloses contacts with Republican members of Congress before the Capitol riot. The lawsuit states Alexander testified that he “had a few phone conversations” with Gosar and spoke to the Arizona congressman Andy Biggs “in person”.

Lawmakers are debating whether sitting members of Congress can be subpoenaed to appear before the committee.

Gosar also has longstanding links to far-right and white nationalist groups.

Last year Gosar was the keynote speaker at an America First Political Action Conference (Afpac) organized by white nationalist Nick Fuentes, whom the Department of Justice in a court filing calls a “white supremacist” and who marched in the deadly Charlottesville “Unite the Right” rally. The January 6 committee is also seeking testimony from Fuentes, who has praised Gosar as supporting his agenda.

“There is some hope, maybe, for America First in Congress, and that is thanks almost exclusively to representative Paul Gosar,” said Fuentes in a video message to his supporters last year.

Gosar distanced himself from Fuentes after outcry over his appearance alongside the white nationalist in a promotion for a fundraising event. But he has also appeared to defend him. Gosar once tweeted: “Not sure why anyone is freaking out. I’ll say this: there are millions of Gen Z, Y and X conservatives. They believe in America First. They will not agree 100% on every issue. No group does. We will not let the left dictate our strategy, alliances and efforts. Ignore the left.”

That was not the first time Gosar has incorporated white nationalist themes into his politics.

Last year Gosar and the extremist Georgia congresswoman Marjorie Taylor Greene were linked to an “America First Caucus” that imploded in disarray after planning documents reported by Punchbowl News revealed language that included recruiting people based on “Anglo-Saxon political traditions”.

Gosar was also censured and stripped of his committee posts late last year after tweeting a Photoshopped video of a violent anime sequence depicting him killing congresswoman Alexandria Ocasio-Cortez and attacking President Biden.

“I do not espouse violence towards anyone,” Gosar said during the House debate on his censure. “I voluntarily took the cartoon down, not because it was itself a threat, but because some thought it was. Out of compassion for those who genuinely felt offense, I self-censored.”

But Gosar has a history posting of far-right content, including retweeting a QAnon conspiracy theory and a now-deleted tweet of a meme popular in white nationalists circles.

Yet it is now in the area of election integrity that Gosar is becoming most prominent, helping to lead a charge across the US by Republicans claiming that elections in America are vulnerable to fraud and manipulation.

“There’s a comfortable embrace of anti-democratic sentiment,” said Lowndes. “The Republican party hasn’t just opened the door to the far right, but it now relies on the far right.”

At the Arizona rally Gosar told supporters to campaign locally on the election fraud issue. “Take it upon yourself that in your county you go to your county recorder and ask them what your ballot does. Make them walk you through it. That’ll tell them one thing: that you’re watching them. That you’re not going to let this happen, what happened in January of last year.”

Gosar was among the Arizona Republican officials pushing for an audit of the election results of Maricopa county, the state’s most populous county. Before the Trump rally, the Maricopa elections department released a 93-page report rebuking each of the 76 claims about the 2020 elections made by elected Arizona Republican officials.

The report found “the November 2020 General Election was administered with integrity and the results were accurate and reliable.” The report also found “despite all evidence to the contrary, false allegations continue to persist and damage voter confidence.”

But there is at least one group of people close to Gosar who are not fooled – some of his own family.

Three of Gosar’s siblings have publicly called for their brother to be expelled from Congress, the Arizona Republic has reported. “We know him to be an extremist and we took that very seriously,” his sister, Jennifer Gosar, told the newspaper. His brother, Dave Gosar, told NBC News: “I consider him a traitor to this country. I consider him a traitor to his family.” In the 2018 election six of Gosar’s nine siblings endorsed his opponent.