A federal law makes it a crime for lots of people to have guns. It is, Justice Samuel A. Alito Jr. wrote in 2019, “no minor provision.”

“It probably does more to combat gun violence than any other federal law,” he wrote. “It prohibits the possession of firearms by, among others, convicted felons, mentally ill persons found by a court to present a danger to the community, stalkers, harassers, perpetrators of domestic violence and illegal aliens.”

Since then, however, the Supreme Court has interpreted the Second Amendment in a way that puts major parts of the law at risk and has left lower courts in, as one challenger put it, a “state of disarray.” Given the conflicts in the federal appeals courts and the importance of the law, the justices will soon have to intervene.

All of this is a consequence of a 2022 Supreme Court decision, New York State Rifle & Pistol Association v. Bruen, which created a new test to decide whether gun control laws are constitutional.

The test requires judges to strike down gun laws unless they can locate a historical analogue. Last month, two federal appeals courts issued starkly different decisions on the part of the law that permanently bars people convicted of felonies from having guns.

About 8,000 people were convicted under the law in the year ending in September 2023, receiving average sentences of more than five years. More than 88 percent of those convictions were under the provision barring felons from possessing guns.