Washington. Donald Trump was traveling to Florida on Monday ahead of a history-making federal court appearance this week on dozens of felony charges accusing him of illegally hoarding classified documents and thwarting the Justice Department's efforts to get the records back.

He is the first former U.S. president to get a federal indictment.

Trump’s Tuesday afternoon appearance in Miami will mark his second time since April facing a judge on criminal charges. But unlike a New York case some legal analysts derided as relatively trivial, the Justice Department’s first prosecution of a former president concerns conduct that prosecutors say jeopardized national security, with Espionage Act charges carrying the prospect of a significant prison sentence.

Ahead of his court date, he and his allies have been escalating efforts to undermine the criminal case against him and drum up protests. He's ratcheted up the rhetoric against the Justice Department special counsel who filed the case, calling Jack Smith “deranged" as he repeated without any evidence his claims that he was the target of political persecution. And even as his supporters accuse the Justice Department of being weaponized against him, he vowed Monday to appoint a special prosecutor to investigate President Joe Biden and his family if Trump is elected to a second term.

Trump boarded a plane in Newark, New Jersey, on Monday morning to take him to Miami. Wearing a navy suit and red tie, he gave a quick wave before stepping onboard.

He's encouraged supporters to join a planned protest at the Miami courthouse Tuesday, where he will face the charges and surrender to authorities.

“We need strength in our country now,” Trump said Sunday, speaking to longtime friend and adviser Roger Stone in an interview on WABC Radio. “And they have to go out and they have to protest peacefully. They have to go out.”

“Look, our country has to protest. We’ve lost everything,” he went on.

He also said there were no circumstances “whatsoever” under which he would leave the 2024 race, where he's been dominating the Republican primary.

Other Trump supporters have rallied to his defense with similar language, including Kari Lake, the unsuccessful Republican gubernatorial candidate in Arizona who pointedly said over the weekend that if prosecutors “want to get to President Trump,” they're ”going to have to go through me, and 75 million Americans just like me. And most of us are card-carrying members of the NRA."

Trump's calls for protest echoed exhortations he made ahead of a New York court appearance last April, where he faces charges arising from hush money payments made during his 2016 presidential campaign, though he complained that those who showed up to protest then were “so far away that nobody knew about ’em,” And just like in that case, he plans to address supporters in a Tuesday evening speech hours after his court date.

After his court appearance, he will return to New Jersey, where he’s scheduled a press event to publicly respond to the charges. He'll also be holding a private fundraiser.

Trump supporters were also planning to load buses to head to Miami from other parts of Florida, raising concerns for law enforcement officials who are preparing for the potential unrest around the courthouse. Mayor Francis Suarez was expected to announce additional details Monday about the preparations though there was little police presence near the courthouse — a stark contrast to New York City where police planned for protests for weeks even though no violence ultimately happened.

The Justice Department unsealed Friday an indictment charging Trump with 37 felony counts, 31 relating to the willful retention of national defense information. Other charges include conspiracy to commit obstruction and false statements.

The indictment alleges Trump intentionally retained hundreds of classified documents that he took with him from the White House to his Florida estate, Mar-a-Lago, after leaving the White House in January 2021. The material he stored, including in a bathroom, ballroom, bedroom and shower, included material on nuclear programs, defense and weapons capabilities of the U.S. and foreign governments and a Pentagon “attack plan,” the indictment says. The information, if exposed, could have put at risk members of the military, confidential human sources and intelligence collection methods, prosecutors said.

Beyond that, prosecutors say, he sought to obstruct government efforts to recover the documents, including by directing personal aide Walt Nauta — who was charged alongside Trump — to move boxes to conceal them and also suggesting to his own lawyer that he hide or destroy documents sought by a Justice Department subpoena.