Former President Donald J. Trump was en route to Florida on Monday, a day before his scheduled first appearance in federal court in Miami on criminal charges of mishandling sensitive national security secrets and seeking to thwart the government’s efforts to reclaim classified documents he took with him from the White House.
Mr. Trump is planning to spend Monday night at his Doral resort in Miami, where he and his legal team will be conducting last-minute interviews with lawyers to represent him in the case, before heading to the federal courthouse on Tuesday afternoon.
The authorities in Miami were bracing for the possibility of large crowds of pro-Trump protesters on Tuesday. Mr. Trump has urged peaceful demonstrations, but some of his backers have portrayed this indictment, in an investigation led by the special counsel Jack Smith, as an act of war and called for retribution.
The extraordinary event will be the former president’s second courtroom appearance as a criminal defendant, after his arraignment in April in a New York courthouse on state charges that he falsified business records in connection with a hush-money payment to a porn star just before the 2016 election.
After the hearing, Mr. Trump, who has railed against the new indictment, is expected to fly back to New Jersey. He has announced that he will deliver remarks at his golf club in Bedminster at 8:15 p.m. on Tuesday.
Criminal defendants who are taken into custody before an initial court appearance are often handcuffed, fingerprinted and photographed for a mug shot. In April, however, authorities in New York only took Mr. Trump’s fingerprints and did not handcuff or photograph him.
Mr. Trump’s case has been assigned to Judge Aileen M. Cannon, who earlier handled a lawsuit he filed challenging the F.B.I.’s court-authorized search of his Florida estate and club, Mar-a-Lago. That search came in August, after Mr. Trump had not fully cooperated with a subpoena requiring him to give back all the documents with classification markings that he still had.
Judge Cannon was appointed by Mr. Trump days after he lost the election in November 2020. She surprised legal experts across the ideological divide last year by intervening with various rulings favorable to Mr. Trump, disrupting the documents investigation until a conservative appeals court rebuked her, saying she never had legal authority to intervene. Her assignment to the criminal case was random, the chief clerk for the Southern District of Florida has said.
But Tuesday’s hearing appears likely to be overseen not by Judge Cannon but by a magistrate judge. Magistrate judges handle many of the routine and procedural aspects of court cases.
At the hearing, Mr. Trump is likely to stand quietly next to his lawyer until the judge gives him permission to speak. It is also not yet clear whether Mr. Trump will return for an arraignment later or enter his expected plea of not guilty on Tuesday to eliminate a need to come back for that step.
In the search of Mar-a-Lago, agents found 102 documents marked as classified. Mr. Smith has charged Mr. Trump with 37 counts of unauthorized retention of national security information based on 36 of those documents, along with one that agents found that had no markings and laid out certain “military contingency planning.”
The indictment also details an array of evidence in support of prosecutors’ accusations that Mr. Trump knew he still had classified documents; took steps with his co-defendant, Walt Nauta, to keep them from the government even after being subpoenaed; and caused one of his lawyers to unknowingly lie to the Justice Department about the matter.
On Fox News on Sunday, William P. Barr, Mr. Trump’s former attorney general who has fallen into disfavor with Mr. Trump since refusing to falsely say the 2020 election had been stolen, said that Mr. Trump was “not a victim here.” Mr. Barr added that Mr. Trump appeared to have engaged in “egregious obstruction” to hold on to highly sensitive documents he had no right to retain.
Referring to the assessment of another conservative legal commentator, Andy McCarthy, Mr. Barr also said: “If even half of it is true, he is toast. I mean, it’s a very detailed indictment, and it’s very, very damning.”