The Supreme Court heard oral arguments March 2 in United States v. Hemani, and the federal law banning gun ownership for marijuana users had a rough day. Justices on both sides pushed back hard on the government's position.The statute at issue is 18 U.S.C. §922(g)(3), part of the 1968 Gun Control Act, which bars firearm possession by anyone "an unlawful user of or addicted to any controlled substance." Because marijuana is still federally illegal, that covers every cannabis user in America regardless of state law. The case got to the Supreme Court after the Fifth Circuit struck down the ban as applied to Ali Danial Hemani, a regular marijuana user found with a 9mm during a search of his home.The bench was not buying it.Justice Neil Gorsuch went after the historical logic directly: "Are they all habitual drunkards who would be properly disarmed for life under your theory?" The Founders were regular drinkers, Gorsuch noted. John Adams. James Madison. Under the government's theory, half the Constitutional Convention was disqualified.Justice Amy Coney Barrett drilled into how broadly the statute reaches. It would cover someone who takes a spouse's Ambien without a prescription. She asked whether "it is obvious that a risk of violence would ensue" from that kind of use. The government didn't have a clean answer.Justice Ketanji Brown Jackson was blunter: "Your argument sort of falls apart under the Bruen test."The DOJ is in an awkward spot here. Its new Second Amendment Rights Section is reviewing which federal gun laws to defend, and §922(g)(3) isn't an easy one to stand behind right now. The government still showed up to argue for it, but the tension with the department's broader shift on 2A was hard to miss in the courtroom.Ruling expected by late June. If the court sides with Hemani, §922(g)(3) probably doesn't disappear entirely. More likely, the court requires case-by-case analysis rather than a blanket ban. For the millions of Americans in states with legal cannabis who technically can't own a firearm under current federal law, that distinction matters quite a bit.