WASHINGTON • President Donald Trump has been dealt a new setback in his desperate bid to overturn the US election results, as a federal judge dismissed a lawsuit filed by his campaign that sought to throw out millions of mail-in votes in Pennsylvania.

US District Court Judge Matthew Brann last Saturday ruled that Mr Trump's campaign had failed to demonstrate that there had been widespread voting fraud in the Nov 3 election, which Mr Trump lost to Democrat Joe Biden.

"This court has been presented with strained legal arguments without merit and speculative accusations," Judge Brann wrote, adding that he "has no authority to take away the right to vote of even a single person, let alone millions of citizens".

The lawsuit, spearheaded by Mr Trump's personal lawyer Rudy Giuliani, sought to stop officials from certifying Mr Biden's victory in the state, arguing that some counties wrongly allowed voters to fix errors on their mail ballots.

Mr Giuliani and other Trump lawyers floated a variety of conspiracy theories at a news conference last Thursday as they alleged that the election was marred by widespread voter fraud. But they have had little success in court.

Mr Trump and his allies have now won two election-related cases and lost 34, according to Democratic election lawyer Marc Elias.

Mr Giuliani has signalled in legal filings that he will pursue an appeal, but he has little time to do so before the state formalises Mr Biden's victory today.

"As far as litigation goes, I believe this is the end of the line for them," said Public Interest Law Centre's Mr Benjamin Geffen, who was also involved in the case.

Mr Trump is seeking to invalidate or change election results through recounts and pressure on lawmakers. He would need to prevail in at least three states to prevent Mr Biden from being sworn in as president on Jan 20.

In Michigan, Republicans wrote to the state authorities last Saturday asking them to wait 14 days to certify Mr Biden's victory to allow for an audit of ballots in Wayne County, which includes the majority-black city of Detroit.

The letter cited allegations of "irregularities" that have not been substantiated. Mr Biden won 154,000 more votes than Mr Trump in Michigan.

That effort faces long odds. A spokesman for Michigan's top election authority said state law does not allow for audits before the vote is certified, which is due to take place today. Allegations of widespread fraud have been found to be baseless, the spokesman said.

Two leading Republican Michigan lawmakers who came to Washington at Mr Trump's behest said after meeting him last Friday that they had no information that would change the outcome of the election in the state.

In Wisconsin, an official said poorly trained observers for the Trump campaign were slowing a partial recount by challenging every ballot and raising objections.

"Observers are disruptive. They are asking question after question, telling the tabulators to stop, stop what they're doing and that is out of line, that's not acceptable," Milwaukee County clerk George Christianson told reporters.

Mr Trump's accusations have continued to inflame his hardcore Republican base.

The General Services Administration, run by a Trump appointee, has not recognised Mr Biden's victory, preventing the transition process. Critics said the delay and Mr Trump's refusal to concede have serious implications for national security and the fight against the coronavirus, which has killed more than 261,000 Americans.

REUTERS