What's behind Amy Coney Barrett’s surprise vote on ghost guns?

On Tuesday, the Supreme Court sided against criminals who wish to purchase untraceable guns online for the purpose of committing crimes. Chief Justice John Roberts and Justice Amy Coney Barrett joined the three liberals to preserve a new federal rule that restricts the sale of “ghost guns” to licensed firearm dealers. As part of President Joe Biden’s push against gun violence, ATF issued a rule in 2022 regulating ghost guns under this law, concluding that they fall under the definition of “firearms” because they “may readily be converted” into one. O’Connor ruled that ghost gun kits contain mere “weapon parts,” which ATF has “no general authority to regulate.” And he purported to “vacate” the rule on a nationwide basis, a hotly contested remedy dubbed “nationwide vacatur.” Naturally, the far-right U.S. Court of Appeals for the 5th Circuit refused to stay his ruling, so Biden’s Department of Justice asked the Supreme Court for emergency relief. When it comes back to SCOTUS on the merits, though, Barrett could vote to strike down the rule, since the side debate over O’Connor’s use of “vacatur” would no longer be relevant.