US Supreme Court due to rule on Trump's immunity bid

The US Supreme Court is set to rule on former president Donald Trump's bid for immunity in the case involving his efforts to overturn his 2020 election loss.

The court, whose 6-3 conservative majority includes three justices Trump appointed, seemed inclined during previous arguments to recognise some level of criminal immunity.

Trump is the Republican candidate challenging Democratic President Joe Biden in the November 5 US election in a rematch from four years ago.

However it rules, the court's slow handling of the blockbuster case already has helped Trump by making it unlikely that any trial on the charges could be completed before the election.

The Supreme Court is expected to rule from 10am Monday local time (midnight AEST) on Trump's appeal of a lower court's decision rejecting his immunity claim.

Trump had argued he is immune from prosecution because he was serving as president when he took the actions that led to the charges.

Special Counsel Jack Smith has opposed presidential immunity from prosecution based on the principle that no one is above the law.

During the arguments, Trump's legal team had urged the justices to fully shield former presidents from criminal charges for official acts taken in office.

Without such immunity, Trump's lawyer said, sitting presidents would face "blackmail and extortion" by political rivals due to the threat of future prosecution.

Trump, 78, is the first former US president to be criminally prosecuted as well as the first former president convicted of a crime.

In the special counsel's August 2023 indictment, Trump was charged with conspiring to defraud the US, corruptly obstructing an official proceeding and conspiring to do so, and conspiring against the right of Americans to vote.

He has pleaded not guilty.

Trump's trial had been scheduled to start on March 4 before the delays over the immunity issue.

Now, no trial date is set. Trump made his immunity claim to the trial judge in October, meaning the issue has been litigated for about nine months.

In a separate case brought in New York state court, Trump was found guilty by a jury in Manhattan on May 30 on 34 counts of falsifying documents to cover up hush money paid to a porn star to avoid a sex scandal before the 2016 election.

Trump also faces criminal charges in two other cases. He has pleaded not guilty in those and called all the cases against him politically motivated.

A lawyer for the special counsel's office told the Supreme Court during arguments that the "absolute immunity" sought by Trump would shield presidents from criminal liability for bribery, treason, sedition, murder and, as in this case, trying to overturn the proper results of an election and stay in power.

The timeline of the court's immunity ruling likely does not leave enough time for Smith to try Trump on federal election subversion charges and for a jury to reach a verdict before voters head to the polls.

Trump took numerous steps to try to reverse his 2020 loss to Biden.

Federal prosecutors have accused Trump of pressuring government officials to overturn the election results and encouraging his supporters to march to the Capitol on January 6, 2021, to push Congress not to certify Biden's victory, based on false claims of widespread voting fraud.

Trump supporters attacked police and stormed the Capitol, sending lawmakers and others fleeing. Trump and his allies also are accused of devising a plan to use false electors from key states to thwart certification.

If Trump regains the presidency, he could try to force an end to the prosecution or potentially pardon himself for any federal crimes.