In Massachusetts, the attorney general's office ruled, many years ago, that only guns that they approve of, which have certain features, are legal to sell in the state.
This regulation claimed to stem from CMR 140, the consumer protection law against false advertising.
How is this regulation possibly legal? What is the legal argument that "you can't claim your product does something it doesn't" leads to, "if you don't include these features in your product, it's illegal to sell here"?