Republicans in Congress are embracing Donald Trump’s strategy of attacking the US justice system after the former president’s historic conviction.

Almost no Republican official has stood up to suggest Mr Trump should not be the party’s presidential candidate for the November election – in fact, some have sought to hasten his nomination.

Few others have defended the legitimacy of the New York state court that heard the hush money case against the former president, or the 12 jurors who unanimously arrived at their verdict.

Republicans who have expressed doubts about Mr Trump’s innocence or political viability, including his former national security adviser John Bolton or Senate candidate Larry Hogan, have been criticised by the former president’s enforcers and told to “leave the party”.

Representative Marjorie Taylor Greene said she is voting for Mr Trump “whether he is a free man or a prisoner of the Biden regime”.

The firebrand congresswoman also posted the upside-down US flag that has come to symbolise the “Stop the Steal” movement Mr Trump started with allies before the January 6, 2021, attack on the US Capitol.

Republican senators and representatives are upturning long-standing faith in US governance and setting the stage for what they plan to do if Mr Trump regains power.

On Friday, House Judiciary Committee chairman Jim Jordan demanded the prosecutors Alvin Bragg and Matthew Colangelo appear for a June hearing on the “weaponisation of the federal government” and “the unprecedented political prosecution” of Mr Trump – despite the fact that US President Joe Biden has no authority over the state courts in New York.

“What we’re gearing up for is if Trump wins, he’s going to use the apparatus of the state to target his political opponents,” said Jason Stanley, a professor at Yale and the author of How Fascism Works.

Mr Stanley said history is full of examples of people not believing the rhetoric of authoritarians. “Believe what they say,” he said. “He’s literally telling you he’s going to use the apparatus of the state to target his political opponents.”

At his Trump Tower on Friday in New York, the former president returned to the kinds of attacks he has repeatedly lodged in campaign speeches, portraying Mr Biden as “corrupt” and the US as a “fascist” nation.

Mr Trump called the members of the bipartisan House committee that investigated the January 6 attack on the US Capitol “thugs” and said Mr Biden was a “Manchurian candidate” – a phrase inspired by the 1960s movie portraying a puppet of a US political enemy.

A Trump campaign memo contained talking points for Republican politicians, suggesting they call the case a “sham”, a “hoax” and a “witch hunt”.

Mr Biden faces no such charges, and the House Republicans’ efforts to impeach the president over his son Hunter Biden’s business dealings, have largely stalled. Hunter Biden is due in court next week on an unrelated firearms charge in Wilmington, Delaware.

Mr Biden said “it’s reckless, it’s dangerous, it’s irresponsible, for anyone to say this is rigged just because they don’t like the verdict”.

Asked later at the White House if this could happen to him, Mr Biden said: “Not at all. I didn’t do anything wrong. The system still works.”

As for Mr Trump’s claims the case is being orchestrated by the Democratic president to hurt him politically, Mr Biden quipped: “I didn’t know I was that powerful.”

In the hush money case, Mr Trump was found guilty of trying to influence the 2016 election by falsifying payment to a porn actor to bury her story of an affair. He faces three other felony indictments, including the federal case over his effort to overturn the 2020 election. But they are not likely to be heard before November’s expected election rematch with Mr Biden.

Thursday’s verdict came after a jury in 2023 found Mr Trump to be liable for sexual abuse against advice columnist E Jean Carroll and a judge in a 2024 business fraud case determined that Mr Trump lied about his wealth for years, ordering him to pay 355 million US dollars (£279 million) in penalties.

Almost to a person, the Republicans in Congress who spoke out provided a singular voice for Mr Trump.

Speaker Mike Johnson on Fox News amplified the claim, without evidence, that Democrats are trying to hurt Mr Trump. He said he thinks the Supreme Court should “step in” to resolve the case.

“The justices on the court, I know many of them personally, I think they’re deeply concerned about that as we are,” the Republican speaker said.

The outgoing Senate Republican leader, Mitch McConnell, said he expected Mr Trump would win the hush money case on appeal, but the three senators seeking to replace him as leader echoed Mr Trump with stronger criticisms of the judicial system.

House Republicans better prepare to take action.

Words are meaningless.

We control the House of Representatives.

We hold the power of the purse.

We have subpoena power.

We go back in session next week on Monday.

No more excuses.

— Rep. Marjorie Taylor Greene🇺🇸 (@RepMTG) May 31, 2024

South Dakota Senator John Thune said the case was “politically motivated”, Texas Senator John Cornyn called the verdict “a disgrace” and Senator Rick Scott of Florida said that everyone who calls themselves a party leader “must stand up and condemn” what he called “lawless election interference”.

And Senator Susan Collins, the Maine Republican who is known as a bipartisan leader, said the prosecutor “brought these charges precisely because of who the defendant was rather than because of any specified criminal conduct”.

With sentencing in the hush money case expected in July before the Republican National Convention, Republican representative Chip Roy said the Republican Party should move up the convention to accelerate Mr Trump’s nomination as the party’s presidential pick.

Republican judicial advocate Mike Davis, a former top Senate aide tipped for a future Trump administration position, circulated a letter outlining the next steps.

“Dear Republicans,” he said in a post on Friday. If their response to the guilty verdict was “we must respect the process” or “we are too principled to retaliate”, he suggested they do two things: One was an expletive, the other: “Leave the party.”

Senator Mike Lee, a Utah Republican, circulated his own letter in which he suggested it was the White House that “made a mockery” of the rule of law and altered politics in “un-American” ways. He and other senators threatened to stall Senate business until Republicans take action.

“Those who turned our judicial system into a political cudgel must be held accountable,” Mr Lee said.