State Attorneys General Ask Courts to Preserve Biden-era Gun Control Measures

More than a dozen state attorneys general, all Democrats, asked on Thursday to join federal legal efforts to preserve two Biden-era gun control policies, a signal of partisan legal fights to come as President-elect Donald J. Trump returns to power.

The two policy shifts are different. One would require buyers at gun shows to undergo a background check, a rule by the Bureau of Alcohol, Tobacco, Firearms and Explosives that is almost sure to clash with the views of Mr. Trump, who promised in a campaign speech to the National Rifle Association to “roll back every Biden attack on the Second Amendment.” The other, to ban a kind of trigger that can make a semiautomatic weapon fire like a machine gun, is similar to a policy that Mr. Trump embraced in his first term when he banned so-called bump stocks, which achieve the same purpose.

But the intervention is the first sign that partisan legal fights are likely to begin on Day 1 of the Trump White House, despite the wishes of some Democratic politicians who have called for a more cooperative stance toward the incoming administration after four years of incessant fighting in Mr. Trump’s first term.

“We know it’s a very real likelihood, based on what the president-elect has said, that his Justice Department won’t defend these rules,” Attorney General Matthew J. Platkin of New Jersey said in an interview, referring to Mr. Trump, who becomes president on Monday. “States like New Jersey will be harmed.”

After Mr. Trump’s victory in November, some Democrats called for compromise where possible. The move by the attorneys general shows they are more than ready to go to court to block Mr. Trump’s aggressive agenda, as many did during his first term.

Mr. Platkin’s office led a motion filed Wednesday in the U.S. District Court for North Dakota as well, this time to intervene on behalf of a group of undocumented immigrants. That case, which began as a lawsuit by 19 Republican states against the Biden administration, challenges a policy that allows some undocumented immigrants already legally authorized to stay in the United States to also receive subsidized health insurance under the Affordable Care Act.

Those immigrants were brought to the country as children and granted conditional legal status under the Deferred Action for Childhood Arrivals, or DACA, program. New Jersey and 13 other states have filed a motion to intervene, which would allow them to join the case as defendants. That would allow them to continue fighting for the existing policy in court if Mr. Trump’s Justice Department decides to drop out.

The Democrats seek to achieve the same end on the two gun control regulations.

Republican-led states have repeatedly sued to reverse President Biden’s agenda as well, with Texas often leading challenges to federal policies on immigration, and rules around the Covid-19 pandemic. Twenty-six Republican attorneys general sued last year to challenge the administration’s new requirement of background checks for buyers at gun shows, which White House officials said was facilitated by a relatively modest gun law passed in the aftermath of the school shooting in Uvalde, Texas, that killed 19 children and two teachers. Republicans accused President Biden of overstepping the law, and suits over the background check regulation are now being heard by four district courts.

The second gun control measure that the Democratic attorneys general want to keep is a federal ban on “forced-reset triggers,” an accessory that allows gun owners to fire their semiautomatic weapons more rapidly. The triggers are somewhat similar in their intended effect to bump stocks, which Mr. Trump’s administration banned during his first term. “We will BAN all devices that turn legal weapons into illegal machine guns,” Mr. Trump posted on social media in 2018.

Mr. Trump’s ban on bump stocks was overturned in 2024 by the Supreme Court. President Biden’s forced-reset trigger ban was struck down that same year by Judge Reed O’Connor of the Northern District of Texas, before going to the U.S. Court of Appeals for the Fifth Circuit, which heard arguments in December.

A spokesman for Mr. Trump did not immediately respond when asked if the incoming administration would maintain the ban on forced-reset triggers. Mr. Platkin, the New Jersey attorney general, said that more recent statements by Mr. Trump led him to believe that it would not.

“There’s been enough said during the course of the campaign that give us pause,” Mr. Platkin said. “We have to step in to protect our residents.”