Republican Senator Ron Johnson, one of Donald Trump's most loyal allies in Congress, was caught on video blaming the former president for his election defeat in 2020.

Mr Johnson made the comments to a liberal activist pretending to be a conservative while she questioned him during an event in Milwaukee. The woman pretended to buy into Mr Trump's election conspiracy theories, and suggested that voter fraud was the reason the former president lost in Wisconsin.

Mr Johnson tells the woman that he disagreed, noting that there was "nothing obviously skewed about the results”.

“If all the Republicans voted for Trump the way they voted for the Assembly candidates, he would have won. He didn’t get 51,000 votes that other Republicans got, and that’s why he lost,” Mr Johnson said.

Mr Johnson was asked about the incident by The Washington Post. He defended his comments, saying they were in line with his other public statements, but complained that a "Democrat political operative" recorded him without his knowledge.

“Ever since the Electoral College met, I acknowledged that former vice president Joe Biden was the president-elect and repeatedly said I could not envision any scenario where any Biden electors would be rejected,” he said.

He noted that in the past he “acknowledged that we should respect our system of individual state certification of election results, and that in Wisconsin, there is nothing obviously wrong with the statewide results”.

Despite his comments, the senator still backs an election audit in Wisconsin similar to the much-maligned audit in Maricopa County, Arizona.

Joe Biden defeated Mr Trump in the 2020 election by 21,000 votes, and despite numerous challenges and recounts, no evidence has ever emerged to suggest voter fraud occurred.

“There were many irregularities that have yet to be fully explained, fully investigated, and solutions passed to restore confidence in future elections,” Mr Johnson said. “I’ve investigated many of the irregularities, explained some, and have not gotten answers on many.”

While previous calls for election audits have focused on conspiracy-driven concerns over the legitimacy of voting machines, Mr Johnson said "the last thing I'd focus on would be the machines," admitting that Republicans were "too concentrated on the machines”.

Wisconsin's legislature recently approved diverting up to $680,000 in public funds to conduct an audit of the state's election results.

Much like the Maricopa County audit, Wisconsin's audit will be led by an avid Trump supporter who repeated the former president's election conspiracy theories, former state Supreme Court Justice Michale Gableman.

Wisconsin's Governor Tony Evers, a Democrat, said the audit was a "continued attack on our democracy," calling it "outrageous”.