Donald Trump won a major legal victory on Monday when a federal judge dismissed one of the criminal prosecutions against him, as he prepared to accept the Republican Party’s presidential nomination just days after surviving an assassination attempt.

A US judge in Florida appointed to the bench by Trump dismissed the case that accused the former President of illegally holding on to classified documents after leaving office, ruling that the prosecutor handling the case was unlawfully appointed to his role.

The news comes at outset of the 2024 Republican convention in Milwaukee, where Trump will announce his vice presidential pick and on Thursday is due to formally accept the party’s nomination to challenge Democratic President Joe Biden in the November 5 election.

Trump, 78, and Biden, 81, are locked in what opinion polls show to be a tight rematch. Trump continues to claim that his 2020 loss to Biden was the result of widespread fraud and has not committed to accepting the results of the election were he to lose.

The race was upended on Saturday when Trump was shot in the ear at a rally in Pennsylvania by a 20-year-old gunman whose motive remains unknown.

In the wake of his near-death experience, Trump said he is revising his acceptance speech to emphasize national unity, rather than highlight his differences with Biden.

“This is a chance to bring the whole country, even the whole world, together. The speech will be a lot different, a lot different than it would’ve been two days ago,” Trump told the Washington Examiner.

Trump said that following the judge’s decision on Monday dismissing the documents case, his other outstanding prosecutions should also be thrown out. He is still awaiting trial on two cases — a federal prosecution in Washington and a Georgia state prosecution — for his attempts to overturn his 2020 election defeat.

The July 1 Supreme Court ruling that he has immunity for many actions he took as President could hamstring both those cases.

Trump is also due to be sentenced in New York in September for trying to cover up a hush-money payment to porn star Stormy Daniels in the weeks before his 2016 election victory.

“This dismissal of the Lawless Indictment in Florida should be just the first step, followed quickly by the dismissal of ALL the Witch Hunts,” Trump said on his Truth Social site on Monday, also referencing the prosecutions of hundreds of his supporters who stormed the US Capitol on January 6, 2021.

US district judge Aileen Cannon, who was appointed to the bench by Trump, ruled that Special Counsel Jack Smith, who is leading the prosecution, was unlawfully appointed to his role and did not have the authority to bring the case.

It marked another blockbuster legal triumph for Trump, following a July 1 US Supreme Court ruling that as a former President he has immunity from prosecution for many of his actions in office.

Prosecutors are likely to appeal the ruling. Courts in other cases have repeatedly upheld the ability of the US justice department to appoint special counsels to handle certain politically sensitive investigations.

A spokesperson for Smith did not immediately respond to a request for comment.

At the very least, Cannon’s ruling throws the future of the case into doubt. Smith is also prosecuting Trump in federal court in Washington on charges involving the former President’s attempts to overturn the 2020 election, but his lawyers have not made a similar challenge to the special counsel in that case.

In the documents case, Trump was indicted on charges that he wilfully retained sensitive national security documents at his Mar-a-Lago estate after leaving office in 2021 and obstructed government efforts to retrieve the material.