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 next 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-Penn., 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 (9 meters) 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 an interview.

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 mishandling 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, Florida.

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.

In an interview this past week, Heinrich said, “It is outrageous to think — the cavalier nature with which the former president treats information, that can have life or death consequences for our sources, is unfathomable.”

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.

Trump attorneys had insisted early in the summer after the first delivery of returned documents that there was nothing left at the former president’s club. Upon inspection, the FBI asked the storage room to be put under lock and key. Ultimately a search warrant for Mar-a-Lago was obtained and more than 100 other documents with classified markings were found. Now, the Justice Department is investigating the Trump team’s handling of the documents and possible obstruction.

Cornyn expressed skepticism the stashed documents held critical information.

“It’s hard for me to believe it was particularly sensitive — it’s been sitting at Mar-a-Lago for a year and a half before they do anything about it,” he said.

Still, when it comes to handling classified documents, Cornyn noted: “There are ways to secure it, but it’s not — under no circumstance, should it be in your home.”

Retribution for breaking secrets on Capitol Hill can be swift and severe. In the 1980s, Sen. Patrick Leahy, D-Vt., announced he would leave the Intelligence Committee after acknowledging that he had allowed a reporter to review a not classified but still “committee confidential” draft report on the Contra wars in Latin America. More recently, a former senior staff member of the Senate panel was charged with lying to investigators about his interactions with journalists.

Immediately after the Mar-a-Lago search, Sen. Mark Warner, the Democratic chairman of the intelligence committee, and Rubio jointly asked the director of national intelligence for an assessment of the damage to national security that would result from disclosure of the documents.

“My issue is not whether the documents belong there or not, because ultimately they shouldn’t have been stored there and they could have been removed,” Rubio said in an interview. “The question is: Was there good faith efforts made by the federal government to retrieve those documents without resorting to a raid of a former president’s home?”

The intelligence office was expected to provide a bipartisan briefing for the so-called gang of eight — the top four leaders of the House and the Senate, along with the House and Senate intelligence committee leaders.

But it is uncertain now, due to Trump’s litigation, whether the Office of the Director of National Intelligence will be able to continue the assessment or provide the briefing to lawmakers.

Warner said he was asking for at least an interim risk assessment.

Senators expect the gang of eight briefing could happen next week, when the House and Senate are both back in session — but only in a secure location.