House Democrats are looking to roll back a little-known, five-decade-old Capitol Hill regulation that allows members of Congress to keep guns in their offices and carry them around the Capitol grounds.

The effort has been spearheaded by Rep. Jared Huffman (D-Calif.), who has pressed Capitol Hill authorities to revisit the 1967 regulation for months, and he now has the support of Rep. Nancy Pelosi (D-Calif.), who has been nominated by her party to become House speaker early next year.

“I don’t think we can just keep looking the other way or sweep this issue under the rug,” Huffman said in an interview, citing potential threats to public safety and national security from a lost or stolen weapon — or an overheated lawmaker. “Our political climate is too volatile and there are too many warning signs that we need to address things like this.”

It is unclear how common it is for lawmakers to keep guns in their offices. Multiple Republican lawmakers said this week that they are aware of colleagues who keep guns in the Capitol complex but do not know how widespread the practice is. Bringing firearms legally to Capitol Hill involves complying with strict D.C. gun laws, which include a registration requirement.

Huffman said he has heard rumors about colleagues keeping weapons and carrying them on campus but did not have firsthand knowledge about any particular instance. The House Sergeant at Arms, he said, informed him in a briefing that Capitol authorities do not keep records or track which civilians might be in possession of firearms on the grounds.

But any attempt to roll back lawmakers’ ability to keep firearms could become a partisan flash point between the new Democratic House majority — which is likely to pursue new gun control measures — and conservative Republicans who favor gun rights.

A Pelosi spokesman said that, if elected speaker, she would direct authorities to “revisit” the regulations “in the name of ensuring safety and security.”

Rep. Thomas Massie (R-Ky.), chairman of the House Second Amendment Caucus, said any change to existing rules would be about “theatrics” rather than public safety and said it would be hypocritical for Pelosi or other House leaders with a security detail to erode the ability of rank-and-file members to protect themselves.

“It’s proposing to solve a problem that doesn’t exist,” he said. “She’s worried that members aren’t responsible enough to handle a firearm?”

The regulation is in the hands of the Capitol Police Board, a four-member body comprising the sergeants at arms of the House and the Senate, the architect of the Capitol and the chief of the U.S. Capitol Police.

A spokesman for House Sergeant at Arms Paul D. Irving, who chairs the board, declined to comment, citing a policy of not commenting on security matters.

The laws governing firearms on Capitol Hill date to October 1967, months after race riots tore through scores of U.S. cities. President Lyndon B. Johnson signed a federal law explicitly banning weapons on the Capitol grounds for the first time, while also empowering the Capitol Police Board to make exceptions.

The board established those exceptions in a regulation published days after the law went into effect, setting that “nothing . . . shall prohibit any Member of Congress from maintaining firearms within the confines of his office or any Member of Congress or any employee or agent of any Member of Congress from transporting within the Capitol Grounds firearms unloaded and securely wrapped.”

Guns remain completely banned in the legislative chambers themselves and adjacent spaces, barring exceptions from the two sergeants at arms.

For the general public, the law is clear: No guns on the Capitol grounds, even if they are properly registered with D.C. authorities and their owner holds a legitimate concealed-carry permit. Capitol Police routinely arrest and charge people who, usually by mistake, try to bring weapons into congressional buildings.

But Huffman said he is concerned that any loophole for lawmakers opens up the possibility that malicious figures could gain access to guns kept legally within the Capitol. He pointed to the politically motivated shooting last year of House Majority Whip Steve Scalise (R-La.) and other congressional Republicans, as well as the more recent pipe bombs mailed to prominent Democrats, as a reason to act.

“I hesitate to even put in print some of the scenarios that I worry the most about, because the truth is, the House chamber is a place where we occasionally have all of the most powerful government officials in the country gathered in one place,” he said.

In addition to acts by an outsider who gains access to a lawmaker’s weapon, he also raised the possibility of violence perpetrated by a member.

The Capitol has been the site of notable acts of legislator-on-legislator violence, including the 1856 assault of abolitionist Sen. Charles Sumner (Mass.) by proslavery Rep. Preston Brooks (S.C.). After Sumner seemed to insult a slave-owning relative in a speech, Brooks attacked and seriously injured Sumner with a walking cane on the Senate floor.

Huffman first wrote to Irving on May 10 asking “whether Members of Congress have been exempted from the firearms prohibition” for the Capitol and whether any procedures were in place to keep them from transporting guns illegally around the campus.

In a June 25 follow-up letter, he recounted a briefing with Irving and his staff: “I was encouraged to hear that you share many of my concerns about risks and vulnerabilities involving firearms in the Capitol,” Huffman wrote, calling the 1967 regulation “totally unenforceable” and “an honor system.”

“Current regulations would literally allow a member to have a loaded pistol in a desk drawer, file cabinets, or sitting in plain view, or to have a loaded AR15 in an unlocked closet,” he wrote. “It is not hard to imagine unsecured firearms ending up in the wrong hands and tragedy resulting.”

Huffman asked Irving and the police board to require members to sign an acknowledgment of the firearm prohibition rule and brief incoming members on the law. He also proposed that the authorities implement a “randomized, discrete metal detector scan” of two House members during each legislative session. Lawmakers are typically allowed to skip Capitol security checkpoints.

Huffman wrote again on Oct. 25 to “reiterate my concerns” and again ask Irving to brief incoming members on the gun regulation and also “tighten” it “so that the Capitol Police can identify which members or staff are carrying or storing firearms.”

Irving did not reply in writing to the letters, a spokeswoman for Huffman said, but a deputy sergeant at arms informed his office orally that some steps have been taken to educate new members about the gun law on Capitol Hill, including having them sign a written acknowledgment of the rule.

The deputy made no mention of updating the 1967 regulation or conducting random security checks, the spokeswoman said.