Special Counsel Robert Hur’s report on President Biden’s handling of classified documents wasn’t just a devastating evaluation of the president’s mental fitness — it may also turn out to be a legal gift for Donald Trump.

In concluding that Mr. Biden “willfully” mishandled secret information but doesn’t deserve to be prosecuted, Mr. Hur created a clear path for Mr. Trump to argue that he’s facing selective prosecution. That’s the kind of stain that could get the charges tossed altogether.

Mr. Trump faces a 40-count indictment accusing him of mishandling documents and obstructing the investigation. Mr. Biden faces zero counts.

Under Justice Department policy, as a sitting president, he wouldn’t be prosecuted anyway. But Mr. Hur said even without that policy, he didn’t think the case deserved to see a courtroom.

“I do think there is a double standard,” said Curt Levey, president of the Committee of Justice, which advocates for a federal judiciary governed by the rule of law and anchored by the Constitution. He said Mr. Hur “bent over backward finding reasons not to indict.”

Elie Honig, a former federal prosecutor, said he expects Mr. Trump’s team to raise the selective prosecution argument.

“What you have to do is show a judge somebody else did essentially the same thing I did. I was prosecuted. He was not. Now, Donald Trump has a basis to make that motion,” Mr. Honig said on CNN.

Mr. Hur’s report set the political and legal worlds abuzz. His probe began amid the investigation into Mr. Trump when it was revealed that Mr. Biden also had classified documents in his possession.

The classified records were first found inside a Washington think tank on Nov. 2, 2022, but not disclosed to the public until January 2023 — after the midterm elections.

A second batch of documents turned up inside the garage of Mr. Biden’s Wilmington home. Days later, additional classified documents were found inside the president’s home.

Mr. Hur said Mr. Biden had classified materials in his garage, offices and basement den in his Wilmington, Delaware home. He also kept “classified notebooks in unsecured and unauthorized spaces at his Virginia and Delaware homes,” after leaving the vice presidency.

Some of the classified documents were labeled “top secret/sensitive compartmented information,” a category reserved for particularly sensitive material. Among the materials was a 2009 memo he sent to President Obama in an attempt to persuade him not to send more troops to Afghanistan.

Damning photos were included in the report, including a photo showing three notebooks with classified materials stuffed inside cabinets below Mr. Biden’s printer and a television.

Mr. Hur also concluded Mr. Biden disclosed classified information.

But Mr. Hur said the case shouldn’t result in charges, in part because Mr. Biden would be a sympathetic figure for a jury. He said Mr. Biden, in interviews with the special counsel’s office, came across as an “elderly man with a poor memory.”

Jonathan Turley, a law professor at George Washington University, said Mr. Hur’s report was “full of inherent contradictions.”

“It makes the case for how Biden willfully retained and mishandled classified material, but then appears to shrug and decline prosecution,” Mr. Turley said. “It raises the question of whether Biden would have been prosecuted if he was less cognitively challenged or less ‘sympathetic.’ There is an obvious difference in the apparent default position of two special counsels. [Special Counsel Jack] Smith seemed to go after Trump with an abandon where Hur seemed to struggle to abandon any basis for charging Biden.”

Analysts said Mr. Hur’s report was reminiscent of then-FBI Director James Comey’s report on Hillary Clinton’s reckless handling of classified emails, where he said there were elements of a crime, but he doubted intent could be proved because she was too technically inept to understand the national security risks she took.

Elliot Mincberg, senior fellow at People For the American Way, said that’s at the heart of the decision not to charge Mr. Biden but to charge Mr. Trump.

“In these cases involving retention of documents after someone leaves office, which happens a lot, the big question is willfulness. Was there a willful retention?” Mr. Mincberg said. “That makes a huge difference in determining whether to prosecute.”

He said Mr. Trump engaged in what some would argue was “outright lying.” Mr. Biden, meanwhile, “cooperated fully.”

Indeed, that’s how Mr. Hur saw it, saying Mr. Trump’s combative conduct toward the National Archives and Justice Department when they tried to collect the documents set him apart.

Mr. Smith’s 40-count indictment says Mr. Trump not only refused entreaties to return the documents but had others work to conceal what was going on, including an allegation that he tried to delete security camera footage.

“In contrast,” Mr. Hur wrote, “Mr. Biden alerted authorities, turned in classified documents to the National Archives and the Department of Justice in 2022 and 2023, consented to the search of multiple locations including his homes, permitted the seizure and review of handwritten notebooks he believed to be his personal property, and in numerous other ways cooperated with the investigation.”

Joseph Moreno, a former federal prosecutor, said some of the public may be skeptical of that explanation.

“Trump’s case is worse because of his lack of cooperation with the FBI, but we are talking about the same underlying conduct here and Special Counsel Jack Smith’s case will be seen as a blatant political double-standard,” he said.

There are also good arguments for why it should have been easier to make the case against Mr. Biden, at least on the facts.

“As president, Trump had the power to declassify information which the vice president does not,” Mr. Moreno said. “If Biden lacked willfulness to violate the law because he confusedly believed his classified notebooks were his property, why is Trump’s similar argument invalid?”

Mike Davis, a former clerk to Justice Neil M. Gorsuch and president of the judicial conservative advocacy group Article III Project, said Mr. Trump has another plus compared to Mr. Biden: He kept presidential records in an office at his home, which as an ex-president has Secret Service protection.

Mr. Biden’s documents were under no such protections.

Mr. Davis also said Mr. Trump, who was president and possessed declassification powers, could argue his conduct was protected under the Presidential Records Act, whereas Mr. Biden could not.

Another difference in the cases is the prosecutors themselves.

Mr. Hur doesn’t have the same zealous reputation as Jack Smith, the man who’s brought both the classified documents case and an election interference case against Mr. Trump.

“Jack Smith is an incredibly aggressive prosecutor — too aggressive as the courts have said in several cases,” Mr. Levey of the Committee for Justice said. “Hur certainly doesn’t have the pit bull reputation that Jack Smith does.”

• Stephen Dinan contributed to this report.

• Jeff Mordock can be reached at jmordock@washingtontimes.com.

• Alex Swoyer can be reached at aswoyer@washingtontimes.com.