Speaker’s attendance at Trump trial marks a remarkable moment in US politics

House of Representatives speaker Mike Johnson lambasted the United States judicial system on Tuesday as he became the highest-ranking Republican to attend court with Donald Trump, echoing unsubstantiated or disproven arguments made by the former president and his allies.

It was a remarkable moment in modern American politics; the powerful House speaker signalled a turn for his political party against the federal and state legal systems and demonstrated further loyalty toward Trump, who is accused of having arranged secret payments to a porn actress to hide negative stories during his successful 2016 campaign for president.

Johnson – a lawyer who is second in line for the presidency after vice-president Kamala Harris – called the court system “corrupt” and the case against Trump a “sham”, while alleging without proof that the special counsel who’s charged Trump in two separate cases has doctored evidence. He also attacked the credibility of Michael Cohen, Trump’s former lawyer and fixer who began his second day of testimony in the former president's hush money trial.

Trump’s campaign has lined up allies in recent days to appear at the New York courthouse to attack witnesses and others whom Trump is barred by a judge’s gag order from criticising himself.

Also supporting Trump on Tuesday were US Republican Byron Donalds of Florida and North Dakota governor Doug Burgum – both considered possible vice presidential candidates – as well as former GOP candidate Vivek Ramaswamy, one of Trump’s current top surrogates.

Senators JD Vance of Ohio and Tommy Tuberville of Alabama were among those who attended court on Monday.

Their presence and comments critical of the process and its participants have let Trump and his allies amplify their message without risking another explicit violation of a gag order.

Johnson specifically criticised three people Trump is prohibited from insulting. He assailed Cohen as “a man who is clearly on a mission for personal revenge”, said lead prosecutor Matthew Colangelo “recently received over $10,000 in payments from the Democratic National Committee” and said the daughter of Judge Juan Merchan has made “millions of dollars” doing online fundraising for Democrats.

Johnson has been using the pulpit of the speaker’s office in Washington to attack the US judicial system, criticising the courts as biased against the former president, claiming the case is politically motivated by Democrats and insisting Trump has done nothing wrong.

And Johnson, who is dependent on support from Trump to keep the speaker’s gavel, is far from alone. A growing number of Republicans have been turning against the US system of justice in a stark assault as they trek to the courthouse to stand with the indicted former president.

Johnson has aimed to strengthen his alliance with Trump as the speaker has come under fire from his own caucus in the House, including a failed effort at his removal by a fellow Trump backer, Republican Marjorie Taylor Greene of Georgia.

Johnson made an appearance with the former president at his Mar-a-Lago club last month to announce new House legislation to require proof of citizenship for voting, echoing Trump’s baseless claims that Democrats are abetting immigrants entering the US illegally to swing elections. There isn’t any indication that noncitizens vote in significant numbers in federal elections or that they will in the future.