Within two months in late 2022, Attorney General Merrick Garland appointed two separate special counsels to investigate the unauthorized retention of classified documents by a former and current president.
One special counsel, Jack Smith, returned with two indictments, alleging that former President Donald Trump violated the Espionage Act as a private citizen and conspired with others to obstruct justice -- charges for which he had pleaded not guilty and denied all wrongdoing.
Thirteen months after his appointment, special counsel Robert Hur on Thursday returned a report recommending against any criminal charges for President Joe Biden, despite finding what he described as ample evidence that the president willingly retained and shared highly classified information as a private citizen.
The diverging fates for the two presidents immediately prompted criticism from Trump, who alleged that the report highlighted a "two-tiered system of justice and unconstitutional selection prosecution."
While the similar nature of the cases is sure to become a political talking point, the stark differences in the conduct of Biden and Trump -- as well as the importance of prosecutorial discretion in national security cases -- resulted in the different results, according to both Hur's report and legal experts who spoke with ABC News.
"One of the most vague areas of national security law and enforcement of it is how to handle retention cases," said Brian Greer, a former CIA lawyer who is now a partner at Greenberg Traurig. "Frankly, retention of classified information happens way more than it should, and the government's just not going to prosecute every case."
Given the uneven enforcement of cases, Greer highlighted former FBI Director James' Comey's decision, months before the 2016 presidential election, not to charge former Secretary of State Hillary Clinton for unlawful transmission of classified documents on a personal device.
"In looking back at our investigations into mishandling or removal of classified information, we cannot find a case that would support bringing criminal charges on these facts," Comey said, citing past cases involving willfulness, intentionality, disloyalty, intentional misconduct, and efforts to obstruct justice. "We do not see those things here."
Hur's report into Biden's conduct appeared to highlight the application of the same discretion, weighing Biden's conduct when he was approached by investigators about the classified documents. While Biden cooperated with investigators who searched his home and office, Trump allegedly engaged in obstructive acts and conspired with others to prevent investigators from recovering classified documents.
"There's no difference in really how they're being approached," Greer said. "If Biden had engaged in the same obstructive acts that Trump had and the same refusal to get the documents back when asked ... he would have been indicted as well."
To preempt comparisons to the Trump case, Hur's report included explicit mention of Trump's conduct compared to Biden's.
"Unlike the evidence involving Mr. Biden, the allegations set forth in the indictment of Mr. Trump, if proven, would present serious aggravating facts," the report noted. "Most notably, after being given multiple chances to return classified documents and avoid prosecution, Mr. Trump allegedly did the opposite."
The combination of Biden's conduct -- as well as concerns about proving the case beyond a reasonable doubt -- resulted in Hur recommending against charges. To prove that Biden violated the law, Hur's team would have needed to show that Biden was not authorized to possess the documents, that the documents related to the national defense, and that Biden's retention of the document was willful.
On the first point, the report conclusively determined that Biden was not authorized to retain the documents, despite his lawyers arguing that the president has the right to keep documents like his diaries. The report also determined that the documents related to the national defense were retained willfully.
The report noted that Biden retained some classified materials documenting his opposition to sending more troops to Afghanistan in 2009.
"Despite Mr. Biden's advice, President Obama ordered a surge of additional U.S. troops, and Mr. Biden's views endured sharp criticism from others within and outside of the administration. But he always believed history would prove him right," the report said.
Biden flagged the ghostwriter of his memoirs to the existence of classified materials in Biden's basement while he was a private citizen, and he appeared to acknowledge keeping some other classified materials.
"They didn't even know I have this," Biden told his ghostwriter in 2016 when referencing his foreign policy notebook, according to Hur's report.
However, investigators found scant evidence that Biden intended to do harm with the documents.
"There's no indication that then-Vice President Biden was intending to keep them for any nefarious purpose," said Robert McWhirter, a criminal and constitutional attorney. "It just seems like an oversight, where Donald Trump Trump's clearly wasn't."
Investigators also noted that many of the records found in Biden's home, at the Penn Biden Center, and at the University of Pennsylvania library "could plausibly have been brought to these locations by mistake."
"The evidence suggests that Mr. Biden did not willfully retain these documents," Hur wrote.
Combined with what Hur's report said was Biden's potential ability to portray himself as a "well-meaning, elderly man with a poor memory," the report concluded that a jury would be hard pressed to find Biden guilty for a crime that relies on a "mental state of willfulness."
A defiant Biden criticized the report's findings -- explicitly comparing his conduct to Trump -- during a White House address Thursday evening.
"It was in my house," Biden said about the classified documents. Referring to Trump's Florida estate, which is also a private club, Biden said, "It wasn't out in Mar-a-Lago in a public place."
"The bottom line is the matter is now closed," Biden said while defending his conduct in comparison to Trump's.
"I did not break the law. Period," he said.
Why Biden and Trump's classified documents cases aren't the same: Experts originally appeared on abcnews.go.com