Former president Donald Trump has railed against the judge who slapped him with a 355 million dollar (£280 million) fine in his New York civil fraud trial while facing penalties that, with interest, could exceed half-a-billion dollars.

Mr Trump was campaigning in Michigan on Saturday – a state that is expected to be critical in November as he pivots towards a likely general election rematch against President Joe Biden.

While Mr Biden narrowly beat Mr Trump here in 2020, the president is facing deep scepticism in the state, especially from Arab-American voters angry over his support for Israel in the Israel-Hamas war as the Palestinian death toll has climbed.

Mr Trump, meanwhile, has been working to appeal to the blue-collar and union voters who were critical to his victory in 2016.

On Saturday, he again made his pitch to auto workers, railing against electric vehicle mandates that he argues will ultimately lead to lost jobs and touted tariffs he put in place.

“We have to let them know a freight train is coming in November,” Mr Trump told more than 2,000 supporters gathered in a freezing plane hangar in Waterford Township, in the suburbs of Detroit.

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Mr Trump opened with a 15-minute screed about the criminal and civil cases against him (Paul Sancya/AP)

But Mr Trump was again most focused on his grievances, opening with a 15-minute screed about the criminal and civil cases against him.

On Friday, a judge in New York ordered Trump to pay 355 million dollars after concluding he had lied about his wealth for years, scheming to dupe banks, insurers and others by inflating his wealth on financial statements.

Mr Trump has vowed to appeal.

That penalty came days after Mr Trump was ordered to pay 83.3 million dollars to the writer E Jean Carroll for damaging her reputation after she accused him of sexual assault.

With interest payments, Mr Trump’s legal debts might now exceed a half-billion dollars — an amount it is unclear whether or not Mr Trump can afford to pay.

Mr Trump cast Friday’s decision as “a lawless and unconstitutional atrocity that sets fire to our laws like no one has ever seen in this country before”.

He called the judge in the case, Arthur Engoron, “crooked”, and New York attorney general Letitia James, who brought the case, a “lunatic”.

He also called special counsel Jack Smith, who brought two federal indictments against him an “animal”, while mocking the pronunciation of Fulton County district attorney Fani Willis’ name.

Mr Trump has succeeded in the Republican primary by casting the charges — which include state and federal criminal indictments across four separate jurisdictions — as part of a co-ordinated effort by Mr Biden and other Democrats to damage his electoral prospects.

He has also repeatedly cast them as an attack on his supporters.

“These repulsive abuses of power are not just an attack on me, they’re really an attack on you and all Americans,” Mr Trump said on Saturday. “We’re all in this mess together.”

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Mr Trump’s visit came as the state’s Republican Party has been in turmoil (Paul Sancya/AP)

But it is unclear whether those appeals will work in a general election, particularly among suburban voters in key swing-state metro areas in places like Oakland County, where Mr Trump was speaking.

An affluent Detroit suburb and the state’s second-largest county, Oakland County was once a Republican stronghold, but has trended more Democratic in recent elections, in part due to women voters.

Mr Trump lost the county to Hillary Clinton in 2016 and Mr Biden in 2020, both times by eight percentage points.

While Michigan will hold its primary next after South Carolina, only 16 out of 55 Republican presidential delegates will be determined by the February 27 vote.

The remaining 39 will be distributed by precinct delegates at a Michigan Republican state convention on March 2.

Mr Trump’s visit came as the state’s Republican Party has been in turmoil, amid competing claims on the chairmanship and financial crisis.

Mr Trump waded carefully into the chaos by offering a shoutout to the newly elected state Republican chairman Pete Hoekstra, a former long-time US House member and Trump loyalist who served as Mr Trump’s ambassador to the Netherlands.

Mr Hoekstra was elected after then-chair Kristina Karamo was ousted after racking up hundreds of thousands in debt.

“A great congressman, and a great ambassador,” Mr Trump said.

A lone man in the crowd still loyal to Ms Karamo, who has said she will not cede the position, booed and called Mr Hoekstra a Rino (Republican In Name Only).