Like former President Donald J. Trump, Lt. Col. Robert Birchum was accused in Florida of mishandling classified documents. Like the former president, he was charged with violating the Espionage Act.
But unlike Mr. Trump, Mr. Birchum, 55, a highly decorated Air Force intelligence officer, took full responsibility. His lawyer said he expressed “true remorse.” He even cooperated with investigators, providing information about how he kept hundreds of secret papers for almost a decade in his home, an overseas office and a storage pod.
Despite all that, Mr. Birchum still got three years in prison when he was sentenced this month.
The case and others like it are warning signs for Mr. Trump, who faces 31 counts of willfully retaining national defense secrets, each of which carries a maximum sentence of 10 years in prison.
The former president has also been charged with conspiracy to obstruct justice, corruptly scheming to hide information from the government and lying to investigators.
Eric Roper, Mr. Birchum’s lawyer, said Mr. Trump was clearly in legal peril.
“Yes, he definitely faces some serious consequences like going to prison if convicted,” Mr. Roper said. “The charges are serious, as evidenced by my client’s sentence and others. And my client did not have any aggravating factors.”
Unlike Mr. Birchum, whose sentence was most likely reduced because he cooperated with prosecutors and was not charged with orchestrating a cover-up, Mr. Trump has signaled no willingness to cede any ground. He has so far said he did nothing wrong and is waging a full-throated attack against federal prosecutors.
The government has accused Mr. Trump of taking hundreds of documents, many of them highly classified, from the White House when he left office in 2021. Prosecutors tried to retrieve the documents, but Mr. Trump resisted, causing the government to obtain a search warrant for Mar-a-Lago, his estate in Florida.
In a 49-page indictment unsealed on Friday, the government detailed 31 classified documents that Mr. Trump had in his possession relating to military and nuclear capabilities of the United States and foreign countries. Other documents included information about military contingency planning, including plans for a potential U.S. attack on Iran.
Prosecutors alleged that Mr. Trump conspired with Walt Nauta, his aide, to obstruct the investigation by hiding documents in a bathroom and other locations at Mar-a-Lago after receiving a subpoena. They also accused Mr. Trump of causing his lawyers to provide false information to the government that all the documents had been accounted for.
During his first run for the presidency, Mr. Trump repeatedly castigated Hillary Clinton, his Democratic rival, for her use of a personal email server during her time as secretary of state under President Barack Obama.
“In my administration,” Mr. Trump said in the summer of 2016, “I’m going to enforce all laws concerning the protection of classified information. No one will be above the law.”
In recent days, allies of Mr. Trump have accused the Justice Department of a double standard, saying they should have prosecuted Mrs. Clinton.
In fact, the cases are very different, with prosecutors accusing Mr. Trump of trying to keep documents from investigators after the subpoena. Prosecutors in Mrs. Clinton’s case said they did not have enough evidence to charge her, including under the Espionage Act. A Justice Department inspector general’s report that looked at Mrs. Clinton’s case did not take issue with that conclusion.
Since 2018, there have been about a dozen criminal prosecutions of people retaining classified or national defense information, according to the Justice Department.
In many of the cases, the defendants received lengthy prison sentences, reflecting how seriously the government takes protecting the country’s secrets.
Two former analysts at the National Security Agency — Harold Martin and Nghia Hoang Pho — received nine years and five and a half years in prison, respectively, for taking classified information home. Mr. Martin, a Navy veteran, admitted that for nearly two decades, he stuffed his home office, car and garden shed with 50 terabytes of information, much of it stamped “classified.” It was one of the largest thefts of classified documents in history, officials said.
In April, Jeremy Brown, 48, a former Special Forces sergeant, was sentenced to seven years and three months in prison for retention of classified information as well as other crimes. Mr. Brown was briefly part of the Oath Keepers, a far-right militia, and was photographed in combat attire during the attack on the Capitol on Jan. 6, 2021.
In that case, Mr. Brown refused to accept responsibility for wrongdoing. During his sentencing, the judge said that he had been “defiant to the end.”
Last year, Kendra Kingsbury, an F.B.I. analyst, pleaded guilty to two counts of unlawfully retaining national security documents at her Dodge City, Kan., home. Prosecutors said she had retained 386 classified documents on hard drives and compact discs.
She is scheduled to be sentenced next week, in a case that will be watched closely by the government and Mr. Trump’s legal team. David Raskin, one of the prosecutors who handled Ms. Kingsbury’s case, is now working for Jack Smith, the special counsel leading the case against the former president.
Mr. Trump’s case is the first time a former president has been charged with a federal criminal violation. But there have been previous instances of prosecutions involving the mishandling of classified information by politicians or highly placed government officials.
All of those cases involved misdemeanor allegations, not felony charges of violating the Espionage Act.
In the late 1990s, John M. Deutch, a former C.I.A. director, was under investigation by the Justice Department for mishandling classified information. He was considering pleading guilty to misdemeanor charges but was pardoned by President Bill Clinton on his last day in office.
In 2005, Sandy Berger, Mr. Clinton’s former national security adviser, was ordered by a judge to pay a $50,000 fine for illegally taking classified documents from the National Archives. Mr. Berger pleaded guilty to a misdemeanor, saying he made an honest mistake while preparing to testify for the 9/11 Commission.
A decade later, David H. Petraeus, another former C.I.A. director, pleaded guilty to a misdemeanor charge of mishandling classified materials. He was placed on probation and fined $100,000.
Mr. Petraeus had kept eight personal notebooks with highly classified information, including identities of covert assets and war strategies, and shared the notebooks with Paula Broadwell, his mistress and biographer.
In his case, prosecutors discovered a recording of Mr. Petraeus and Ms. Broadwell talking about the notebooks.
“I mean, they are highly classified, some of them,” Mr. Petraeus told her. He added, “There’s code-word stuff in there.”
Similarly, in Mr. Trump’s case, prosecutors have a potentially damning recording of the former president talking at his home in Bedminster, N.J., with a writer and a publisher working on a book related to Mark Meadows, Mr. Trump’s former chief of staff.
“Secret. This is secret information,” Mr. Trump boasts as he shows his guests a document. “Look, look at this.”
The government alleges that Mr. Trump later says on the recording that he had not declassified the document he was showing them.
“But this is still a secret,” he says, prompting laughter from someone in the room.
In the case involving Mr. Birchum, he spent more than 29 years as an enlisted airman and officer in the Air Force. He completed several deployments to Iraq and Afghanistan and earned the Bronze Star. In one instance, Mr. Birchum’s intelligence work “supported over 40 strikes against foreign terror networks, resulting in the capture or killing of over 800 enemy combatants,” according to a motion by his lawyer asking for a lighter sentence in his case.
The sentencing memo said Mr. Birchum demonstrated “exceptionally poor adherence” to his obligation to safeguard the nation’s secrets, but he did not keep classified material “for personal gain or with malicious intent to harm the country.”
In that motion — written a month before Mr. Trump’s indictment was unsealed — Mr. Roper, the lawyer, acknowledged the unlikely similarities between an Air Force officer and his commander in chief.
“Among others,” Mr. Roper told the court, his client “now shares a stage” with Mr. Trump.