Miami, Florida - Donald Trump was in a Florida courtroom on Thursday as his lawyers argued for the dismissal of charges against the former president for alleged mishandling of classified documents.

District Judge Aileen Cannon is holding a day-long hearing in Fort Pierce, north of Miami, to hear a pair of dismissal motions filed by Trump's attorneys.

Trump, who is the presumptive Republican presidential nominee, pleaded not guilty in June to federal charges of unlawfully retaining national defense information, conspiracy to obstruct justice, and making false statements.

He kept the classified files – which included records from the Pentagon, CIA, and National Security Agency – unsecured at his Mar-a-Lago home in Florida and thwarted official efforts to retrieve them, per the indictment.

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Trump's lawyers are arguing in court that he had the right to retain the documents under the Presidential Records Act and the indictment should be tossed out.

Special counsel Jack Smith, who filed the charges against Trump, rejected that argument in a court filing.

"Trump was not authorized to possess classified records at all, let alone at unsecured locations at Mar-a-Lago," Smith said, adding that the documents in question – some of which were top secret – were "presidential, not personal" and are therefore government property.

Trump's lawyers are also trying to have the charges dropped on the grounds that the statute under which he was indicted suffered from "unconstitutional vagueness."

"Trump's vagueness argument is meritless," Smith responded. "Trump is charged with the unauthorized possession and willful retention of national defense information. The statute's prohibitions are clear."

Cannon, a Trump appointee, has set a May date for the start of the former president's trial but it is expected to be delayed.

Prosecutors have proposed a July 8 start while Trump's attorneys have asked for the trial to be held after the November election.

Lawyers for the former president have repeatedly sought to delay his various court cases until after the election, when Trump could potentially have the federal charges against him dropped should he win.

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Trump also faces federal charges of conspiring to overturn the results of the 2020 election won by Democrat Joe Biden.

That trial had been scheduled to begin in Washington on March 4 but has been put on hold until the Supreme Court hears Trump's claim that, as a former president, he is immune from criminal prosecution.

The Supreme Court has scheduled arguments in the high-stakes immunity case for April 25.

A three-judge appeals court panel ruled earlier this year that a former president has no immunity from prosecution for actions taken while in the White House.

Trump also faces 2020 election interference charges in Georgia and is scheduled to go on trial in New York on March 25 on state charges of falsifying business records by paying pre-election hush money to a porn star.