He has prosecuted drug dealers, overseen corruption cases and authorized warrants in highly classified investigations.
Now Judge Raymond J. Dearie will take on one of the highest profile — and politically fraught — jobs of his long career: serving as a so-called special master, with a mandate to review a trove of documents seized last month by the F.B.I. during a search of former President Donald J. Trump’s residence in Florida.
Judge Dearie, 78, was officially appointed to the post on Thursday night by Judge Aileen M. Cannon, the Florida jurist who is handling the matter, after emerging as the sole consensus choice between Mr. Trump’s lawyers, who had requested a special master, and the Justice Department, which had opposed the move.
The task ahead of him — sifting through about 11,000 documents and deciding if any are protected by executive privilege or attorney-client privilege or are Mr. Trump’s property — will require both a firm grasp of the law and an innate ability to navigate disputes between opponents.
But Judge Dearie is up for the job, said many of those who know him.
“He’s an ideal choice,” said Alan Vinegrad, a former federal prosecutor who appeared before Judge Dearie in Federal District Court in Brooklyn several times over the years.
“He’s fair,” Mr. Vinegrad said. “He’s thoughtful. He’s measured. He’s careful. And he’s obviously got vast experience. Frankly, it says everything you need to know that both sides of this hotly contested case agreed that he would be a suitable choice.”
Judge Dearie’s role as special master in the case grants him considerable authority over whether, or how quickly, the Justice Department will be able to use classified materials seized from Mr. Trump in its investigation into his handling of the documents and whether the government’s attempts to reclaim them were obstructed.
Under Judge Cannon’s ruling, federal investigators are barred from using the seized materials in their investigation unless or until the special master decides they are not subject to claims of privilege. The Justice Department has argued that Judge Cannon’s ruling also impedes a review of the national security risks by the intelligence agencies.
Judge Cannon’s appointment order gave Judge Dearie broad powers to review materials seized from Mar-a-Lago, Mr. Trump’s residence and private club in Palm Beach, Fla. While examining them for attorney-client privilege is a fairly routine measure, separating out those that may be shielded by executive privilege is a far more unusual move in criminal cases.
Judge Dearie is also authorized to decide which of the records belong to the government and which are Mr. Trump’s personal property — as well to offer his assessment of the documents that the government claims are classified.
Moreover, he has been asked to evaluate any claims by Mr. Trump and his lawyers that the government overstepped the boundaries of the Fourth Amendment and improperly took materials away from Mar-a-Lago during the search.
If there is one criticism made of Judge Dearie, it is that he sometimes takes his time making tough decisions. Judge Cannon has given him a deadline of Nov. 30 to complete his review.
Judge Dearie has been asked to first look at the classified documents taken from Mar-a-Lago and to “thereafter consider prompt adjustments to the court’s orders as necessary.” That seemed to suggest that Judge Cannon would consider allowing the Justice Department to quickly regain unrestricted access to the material for its criminal investigation if Judge Dearie decides that Mr. Trump does not have any valid privilege claims.
Now semiretired as what it is known as a senior status judge, Judge Dearie, a native of Long Island, got his start in the law in 1969 with the Wall Street firm Shearman & Sterling. Two years later, he left private practice and joined the U.S. attorney’s office in Brooklyn, rising through the ranks until he was appointed to the top job in the office by President Ronald Reagan in 1982.
As Brooklyn’s chief federal prosecutor, he made cases against gangsters from New York’s five Mafia families and international drug dealers while earning a reputation as a by-the-book law enforcement official with a measured manner and an affable human touch. In 1986, Alphonse D’Amato, a Republican then representing New York in the Senate, put his name forward for a job on the federal bench. Judge Dearie has now held that position for 36 years.
During his long career, Judge Dearie has overseen prominent criminal cases such as the corruption trials of officials at FIFA, the agency that governs international soccer. He has also handled politically sensitive matters, among them a court battle over who was allowed to participate in televised debates during the 2017 New York City mayor’s race.
Having served on the Foreign Intelligence Surveillance Court from 2012 to 2017, Judge Dearie also has extensive experience with classified proceedings. That experience will likely prove crucial given that Judge Cannon has asked him to begin his review with about 100 highly classified documents seized from Mar-a-Lago.
While sitting on the intelligence surveillance court, Judge Dearie signed off on warrants that the F.B.I. used to surveil Carter Page, a former campaign aide to Mr. Trump, during the bureau’s investigation into Russian interference in the 2016 election. Investigators later discovered that a lawyer for the F.B.I. had altered an email that was used to support the application for the warrant, a development that Mr. Trump and his allies have often used to discredit the larger inquiry.
Many lawyers who know Judge Dearie were surprised last week when Mr. Trump’s legal team suggested him as a candidate for the special master post, wondering if the former president’s lawyers really knew who they were proposing.
“Dearie is a fair-minded, smart judge who has a ton of common sense and has been on the bench for a long time,” said Andrew Weissmann, a former lead prosecutor in the Russia investigation who got his start in the Brooklyn federal courts. “If that’s not what the Trump people wanted, that’s definitely what they got.”
Everything about the search of Mar-a-Lago has taken place in an atmosphere of partisan politics and extreme public scrutiny. As Mr. Trump and his allies have lashed out at the F.B.I. and the Justice Department, federal officials have often felt the need to be more transparent in court filings than usual, agreeing last month to release a redacted version of the affidavit that had been used to apply for the search warrant.
In this hothouse environment, Judge Dearie’s easy manner and natural sense of fairness could prove beneficial, said Jim Walden, a former federal prosecutor who appeared before the judge several times in Brooklyn.
“He’s not going to let the politics affect him,” Mr. Walden said, “and will make decisions without fear or favor for either side.”
Mr. Weissmann said that Judge Dearie’s humility and decency — as well as his ability to read people well — would likely prove useful not only in calming the tempers of the parties in the case, but also in dealing with Judge Cannon, a younger and much less experienced jurist.
When Mr. Weissman was a novice prosecutor, he recalled, Judge Dearie once showed up extremely late for court. A few days later, Mr. Weissman said, he received a handwritten note from the judge apologizing for his tardiness — and soon found out that the defense lawyer in the case had gotten one too.
“He didn’t have to do that, but that’s just who Judge Dearie is,” Mr. Weissmann said.
“He’s a mensch.”