Even as prosecutors publicly unveiled a deep and detailed array of evidence against former President Donald J. Trump in the documents investigation on Friday, they suffered a potential setback with the surprise assignment of the case to Judge Aileen M. Cannon.
Judge Cannon, 42, a Trump appointee in Florida, shocked legal experts across ideological lines last year by intervening in the investigation and issuing rulings favorable to Mr. Trump, only to be rebuked by a conservative appeals court.
The chief clerk of court for the Southern District of Florida has said that new cases there are randomly delegated to its judges even if they are related to previous ones. It was not immediately clear whether Mr. Trump lucked out, or if an exception was made. Either way, legal specialists said Judge Cannon’s return was significant.
The unsealed indictment offered “a strong factual presentation,” said Paul Rosenzweig, a former Bush administration official and federal prosecutor who worked on the independent counsel investigation into President Bill Clinton. “If this were a normal person and a normal case, you’d be talking to your client about pleading guilty. So I think the Cannon draw is actually a serious blow to the prosecution.”
Now that Mr. Trump has been charged — with 37 criminal counts, including 31 violations of the Espionage Act, various charges of obstruction and making a false statement — Judge Cannon may have ample opportunity to issue rulings affecting the tempo and outcome of the case.
For one, substantial evidence described in the indictment comes from Mr. Trump’s own lawyers, raising the likelihood of a fight over whether it should be suppressed as a matter of attorney-client privilege.
That evidence includes a recorded voice memo and witness testimony showing that Mr. Trump kept his legal team in the dark about having had an aide, Walt Nauta, move boxes from a storage room. One lawyer, M. Evan Corcoran, then searched the room for classified material in response to a subpoena and another, Christina Bobb, signed a statement inaccurately saying that all the remaining classified records were being turned over.
Behind closed doors, Mr. Trump and his team had fought a pitched battle to block the special counsel from obtaining that information. But the chief judge of the Federal District Court of the District of Columbia, Beryl A. Howell, ruled that the so-called crime-fraud exception applied, allowing a grand jury in the district to review it.
Those decisions, however, were only about what could be shown to a grand jury. Mr. Trump’s defense team can bring new motions to suppress that evidence and keep the information from reaching the trial jury, and Judge Cannon will not be bound by Judge Howell’s rulings.
Decisions Judge Cannon makes in establishing the pretrial and trial calendar could also be critical. Mr. Trump has long pursued a strategy of trying to run out the clock on legal matters, and if he can push the documents trial beyond the 2024 election, there is a chance that a Republican — whether that is Mr. Trump himself, or another nominee — will become president and end the case.
Because the case involves classified evidence — 31 of the counts against Mr. Trump center on violations of the Espionage Act in the unauthorized retention of 31 secret and top secret documents — it is likely that any judge would spend significant time in handling pretrial hearings over whether to allow substitutions that do not contain classified information.
Samuel Buell, a white-collar criminal law professor at Duke University and former lead prosecutor on the Enron task force, said that there could be “a lot of misdirections and delays and things that may play well in the MAGA media space but I don’t see legally how even a judge inclined to make mischief is going to prevent this from going to trial.”
Still, “out-of-left-field rulings could be coming here,” he said, adding, “When you have classified documents, there is abundant opportunities to slow this down, and if they’ve got a judge who is willing to go along with slowing this down, it becomes very hard to predict when this will go to trial.”
To be sure, there is no guarantee that Judge Cannon will resume the pattern she exhibited last fall. It remains to be seen whether she will respond to the reputational harm it brought her by using a second turn in the spotlight to rule in a more straightforward fashion.
Ryan Goodman, a New York University law professor, said the 31 documents at the heart of the Espionage Act charges were likely carefully selected by Mr. Smith, and after negotiations with national security officials over whether they could be shown to the defense team and potentially jurors if necessary.
One issue that could arise is whether intelligence agencies agree to let Mr. Smith use certain documents with the expectation that he would persuade a judge to keep them from being displayed in open court. If Mr. Trump’s legal team argues that certain documents must be used openly for there to be a fair trial, rulings in his favor could cause the government to consider instead dropping any charges on which those files are based.
Judge Cannon was born in Cali, Colombia, and grew up in Miami. Her mother fled Cuba as a young girl after the 1959 Communist revolution, and her father’s family is from Indiana. She graduated from Duke University and the University of Michigan Law School, clerked for a conservative federal judge, and worked both at a law firm and as a federal prosecutor.
She joined the conservative Federalist Society as a law student in 2005, and was just 39 when Mr. Trump nominated her for a federal judgeship in 2020. Working from a small federal courthouse in Fort Pierce, Fla., north of Palm Beach County, she attracted little attention until her handling of the special master litigation over the search of Mar-a-Lago, Mr. Trump’s club and residence in Palm Beach.
Last year, Judge Cannon oversaw a civil lawsuit filed by Mr. Trump after the F.B.I. searched Mar-a-Lago and seized numerous government documents and other materials stored with them. They included 102 files marked as classified, which Mr. Trump had failed to turn over after receiving a subpoena months earlier.
Judge Cannon temporarily blocked investigators from access to the materials, imposed a special master to vet the files for any that should be permanently kept off limits, entertained the unprecedented idea that some White House files could be kept from criminal investigators in the Justice Department under executive privilege, and set a calendar that threatened to all but freeze the inquiry for at least four months.
Her opinions suggested that a former president should receive greater protections than an ordinary criminal suspect. She also helped Mr. Trump by overruling the special master she had appointed, Judge Raymond Dearie, when he ordered Mr. Trump to certify the accuracy of the F.B.I.’s inventory of property it had seized from his Florida estate.
But the Justice Department appealed and a panel on the Court of Appeals for the 11th Circuit, which included two other Trump appointees, shut down her interference. In a scathing ruling, the panel stated that she never had legitimate jurisdiction to order the review or bar investigators from using the files, and that there was no justification for treating Mr. Trump differently from any other target of a search warrant. The Supreme Court let that decision stand without comment, and Judge Cannon dismissed the lawsuit.
Last fall, this reporter sought clarity on whether Judge Cannon’s involvement with the lawsuit meant she would be automatically assigned any indictment if it were brought in the Southern District of Florida. In email messages, the chief clerk of the court there, Angela Noble, wrote: “We do not assign related cases to the same judge. A related case will still be randomly assigned.”
Still, the odds of an indictment being randomly assigned to Judge Cannon were low. There are 15 active Federal District Court judges in South Florida, along with 11 on senior status who are still assigned to hear cases but at a reduced workload. Ms. Noble did not immediately respond to an email seeking clarification of what happened.
Mr. Trump and his team have already signaled that they intend to raise accusations of misconduct by prosecutors and investigators, as they did this month in a meeting at the Justice Department trying to head off an indictment.
Criminal defendants routinely claim that prosecutors threatened witnesses and committed other misconduct, and they rarely succeed. But if Judge Cannon entertains those claims more deferentially than trial judges normally do, Mr. Smith and his team could effectively go on trial before Mr. Trump.
“Pretrial litigation over the conduct of prosecutors is a good one for gumming things up and fits with Trump’s message, which is going to be out of control, politically motivated prosecutors,’” Mr. Buell said. “So we will see plenty of that.”