WASHINGTON — Security-sealed rooms. Lock bags. And in the most rare of circumstances, the ability to handcuff a document pouch to a messenger to transport the nation’s secrets.

These are some of the ways Capitol Hill keeps classified documents secured, an elaborate system of government protocols and high-level security clearances that stands in stark contrast to the storage room stash of secrets at Donald Trump’s Mar-a-Lago estate in Florida.

As the Justice Department’s probe into the Republican former president’s possession of White House materials deepens, lawmakers of both parties have more questions than answers. Intelligence officials have offered to brief congressional leaders, possibly as soon as this week, senators said, as they launch a lengthy risk assessment. Congress had asked for the briefing soon after the revelation of the unprecedented Aug. 8 search, but it may be delayed by the legal fight between Trump and the government.

“We need to be able to do appropriate oversight for the Intelligence Committee so that we have a better handle on how this particular incident was handled, but so that we avoid problems like this in the future,” said Sen. John Cornyn, R-Texas.

A culture of secrecy may not necessarily be expected from Capitol Hill, where 535 elected members of Congress — alongside thousands of aides and countless more visitors — broker information on a daily basis as a routine part of governing.

Secrets large and small — from the most mundane details about when an upcoming vote will be scheduled to the parlor intrigue of transitional alliances — are among the more valued bits of currency that pass through the place.

But when it comes to classified materials, the stream of information tends to clamp shut.

Lawmakers who serve on the House and Senate Intelligence committees are traditionally among the most publicly tight-lipped about their work, and staff for those panels must obtain security clearances to handle the documents and perform their jobs. Others serving on committees dealing with military affairs and certain national security funds face similar restrictions.

When members of Congress want to peruse classified materials, they descend deep into the basement of the Capitol to a sensitive compartmented information facility, known as a SCIF. Other SCIFs are scattered throughout the Capitol complex.

If documents need to be ferried in or out of secure locations, they are typically transported in a lock bag, a briefcase-sized pouch under lock and key.

Sen. Bob Casey, D-Pa., a member of the Intelligence Committee, said staff will often use a lock bag even simply to transport materials from committee offices to a SCIF some 30 feet away.

“The idea that anyone would leave any building or any room with those documents not secure — it’s just, the word is, unfathomable,” Casey said.

In rare instances, a document pouch can be handcuffed to a person’s wrist for travel, though several senators and staff said they have never seen that happen.

“I’ve only seen that in movies,” said Sen. Marco Rubio of Florida, the top-ranking Republican on the Intelligence Committee.

Trump’s alleged mishand-ling of the documents has stunned lawmakers of both parties, even those Republicans critical of the Justice Department’s unusual search of a former president. Court filings from the federal government say hundreds of classified records have been retrieved from Trump’s private Mar-a-Lago club in Palm Beach, Fla.

Sen. Martin Heinrich, D-N.M., all but warned of Trump’s handling of sensitive documents early in the then-president’s term. A photo from a White House press briefing in 2017 showed Trump and others in the Oval Office with a lock bag visible on the desk, the key still inside.

“Never leave a key in a classified lock bag in the presence of non-cleared people. #Classified101,” tweeted Heinrich, a member of the Intelligence Committee, days after the February 2017 incident. He asked for a review.

“The cavalier nature with which the former president treats information that can have life-or-death consequences for our sources is unfathomable,” Heinrich said last week.

Trump amassed more than a dozen boxes of papers and other mementos from the White House, many held in a storage room at Mar-a-Lago. The FBI’s search came after a protracted battle over missing documents launched soon after Trump left the White House in 2021.

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