California Gov. Gavin Newsom must not have enough to do because he is spending much of his time trolling Republicans in other states. First it was Florida on Disney, and now it’s Texas, with a new law modeled on the Lone Star State’s abortion law that charges private citizens with enforcing a state ban on so-called assault weapons. Mr. Newsom’s gambit could do broader harm, as the American Civil Liberties Union warns.

Democrats in Sacramento last month enacted legislation creating a private right of action to sue gun makers and distributors for imported firearms that violate the state’s gun laws. California law prohibits more than 50 models of semiautomatic rifles, pistols and shotguns that Democrats call assault weapons though many are in common use.