How common is the keeping of classified documents in the US?

New information shows that at least three US presidents and a vice president have taken state secrets with them after leaving office

Boxes removed from the Eisenhower Executive Office Building, where the vice president works, in Washington. AP

Leaders elected to top offices in the US must take an oath to keep the country's national secrets in perpetuity — but the physical documents pertaining to that intelligence, especially when marked Top Secret, should not be taken home after leaving office.

Former vice president Mike Pence's lawyers on Tuesday announced that about a dozen classified documents had been found in his home, days after the Department of Justice obtained government files during an FBI search of President Joe Biden's Delaware residence.

And those discoveries come after the US government revealed former president Donald Trump had held on to hundreds of classified documents after his presidency ended.

The back-to-back revelations are ringing alarm bells about the lax security around highly sensitive documents that could threaten foreign relations, national security and even the lives of covert operatives.

“Countries should be alarmed that we are failing to properly safeguard national secrets,” University of Michigan Law professor and former US prosecutor Barbara McQuade told The National.

“Long term, a failure by the US government to safeguard the secrets of our allies could result in their refusal to share secrets with us, which will further harm our own national security.”

Earlier, Mr Biden's lawyers had contacted the Department of Justice to hand over the classified documents found in his home and former office. As a result, a rare federal investigation was opened into a current US president who may run for re-election in 2024.

What's happening with Joe Biden and the classified material discovery? - video

“It is unlikely that Biden will be prosecuted because there is no evidence that he knowingly and wilfully possessed the classified documents,” Chicago lawyer Renato Mariotti, who oversaw federal investigations as a prosecutor, told The National.

The “loss or removal of national defence information” would have to involve “gross negligence” for a person to be charged under the US Espionage Act, he said, which is “almost never prosecuted”.

“It doesn’t look like that evidence exists here,” Mr Mariotti said.

The findings come as Mr Trump is embroiled in a federal investigation into a potential obstruction of justice due to his possession of hundreds of classified documents after his presidency ended.

In an ABC News/Ispos survey, a majority of Americans said Mr Biden and Mr Trump inappropriately handled classified documents, and most regarded Mr Trump's actions as more serious.

“With both Mr Pence and President Biden appearing to offer co-operation in the return of the classified records, Mr Trump is increasingly alone on a legal island with his documented obstructive actions prior to the raid on Mar-a-Lago,” Bradley Moss, a lawyer in Washington, told The National.

More commonplace than previously thought

With differences in co-operation and intent in Mr Trump's case aside, the discoveries at Mr Biden's and Mr Pence's residences “suggest that accidentally retaining documents is not as rare as we thought”, Ms McQuade said.

The Associated Press reported on Tuesday that authorities regularly receive documents inadvertently taken by former officials, highlighting a bigger problem that many in the US are unfamiliar with.

Former president Jimmy Carter, for example, reportedly found classified materials at his home at least once and returned them to the National Archives.

“However, we should expect our leaders to treat national secrets with care, and these lapses may tend to diminish public confidence in Biden,” Ms McQuade said.

The revelations may say more about how organised — or rather disorganised — transfers of power in the US are.

“These matters suggest that Congress should consider conducting oversight and appropriate legislation to ensure that classified materials are not mishandled in connection with future presidential transitions,” Mr Mariotti declared.

They also show potential holes in governance over national security information.

“Our government needs to do a better job of controlling access to classified documents,” Ms McQuade said. “A chain of custody should be maintained, and all documents returned or destroyed when the reader is done reading them.”

'Over-classification'

The Public Interest Declassification Board at the National Archives said in a tweet last week: “Another scandal regarding classified material: There's too much of it.”

“The classification system as a whole is clearly in disrepair,” Mr Moss, experienced in national security and security clearance law, told The National.

“There is simply too much classified information floating around and it is not possible to properly manage all of it without spillage. If ever there was a bipartisan moment to truly consider the need for better oversight and reform of that system, one would hope that now is that moment.”

The board in 2020 presented options for simplifying classification tiers and allowing automation to help the agency manage the mammoth of documents it handles.