Washington DC - The US Supreme Court will hear a challenge Tuesday to the use of a law behind one of the charges lodged against former President Donald Trump and hundreds of his supporters who took part in the January 2021 attack on the Capitol.

Special Counsel Jack Smith has slapped the 77-year-old Trump with four federal felony charges in Washington related to efforts to overturn the results of the 2020 election he lost to Democrat Joe Biden.

The Republican presidential candidate is charged with conspiracy to defraud the US, conspiracy to obstruct an official proceeding, and conspiracy to deny Americans the right to vote and to have their votes counted.

He is also charged with obstruction of an official proceeding – the January 6, 2021 joint session of Congress held to certify Biden's victory.

Donald Trump Trump scores big win as hush money trial sentencing is delayed again

Joseph Fischer, a former police officer, is among hundreds of Trump supporters facing or convicted of the same obstruction charge and is seeking to have it dismissed, which could have a knock-on effect for all the cases, including Trump's.

A federal district court judge, a Trump appointee, agreed to throw out Fischer's obstruction charge on the grounds that the law was intended to prosecute financial crimes following the Enron scandal and did not apply to his conduct on January 6.

That ruling was reversed by an appeals court in a 2-1 decision.

Now the Supreme Court, which has a 6-3 conservative majority – including three justices nominated by Trump – will hear Fischer's appeal.

The nation's highest court is expected to issue a ruling by the end of its term in June or in early July, around four months before the November 5 presidential election in which Trump is expected to face Biden again.

Trump's trial on the election interference charges had been scheduled to begin on March 4 but is currently on hold pending a Supreme Court examination of Trump's claim that as a former president, he is immune from criminal prosecution.

Melania Trump Melania Trump reportedly teams up with RFK Jr. to revamp Donald's "poison" diet

The Supreme Court is to hear arguments on the immunity claim, which has been dismissed by two lower courts, on April 25 and issue a ruling by the end of its term.

A conviction for obstruction of an official proceeding carries a maximum sentence of 20 years in prison.

There are four criminal cases hanging over Trump as he seeks to recapture the White House, and jury selection began in New York on Monday in his hush money trial – a first for a former president.