“The emerging research shows they are very effective,” Feinblatt said of red-flag laws in a phone interview yesterday. He said the various state laws have been used more than 1,700 times in total, including a notable case in Vermont in which the law allowed authorities to bar a teenager who had detailed plans to shoot up his school from buying weapons. “This is a tool that allows law enforcement and immediate family members to act,” Feinblatt told me.

A red-flag law would be the most significant action Congress has taken on guns in years. In 2018, the House and Senate took a modest step by enacting the Fix NICS Act to encourage states and the military to upload records to the federal background-check system. The Trump administration also acted unilaterally to ban bump stocks, the rapid-fire attachment that was used in the 2017 Las Vegas massacre.

Advocates of red-flag laws say they have proved successful in preventing not only murder but suicide. The National Rifle Association voiced support for the concept of red flags after the Parkland shooting in 2018, but the gun lobby has worked to weaken or defeat proposals when they’ve come up for votes in the states. “Someone could be stripped of their Second Amendment rights without due process, without being taken into custody for any criminal offense or without being required to undergo evaluation for treatment by a mental health professional,” the NRA wrote about a proposal in Texas earlier this year.