Members of Congress from states that have legalized marijuana are complaining about Attorney General Jeff Sessions’ announcement that the Justice Department will enforce federal laws against weed. Their critics have said that their proper remedy is to get Congress to change federal law.

How to do that, with the votes lacking for legalization? One model is the 21st Amendment to the Constitution, which repealed the Eighteenth Amendment imposing prohibition of alcohol.

Section 2 of the 21st Amendment reads: “The transportation or importation into any State, Territory or possession of the United States for delivery or use therein of intoxicating liquors, in violation of the laws thereof, is hereby prohibited.”

In other words, the Repeal amendment allowed the states to continue to prohibit alcohol, as several did, with political support coming often from an alliance of Baptists and bootleggers, and the federal government was authorized to help the states enforce those laws. In this case, the federal norm would be prohibition, but it would recognize and honor legalization by the states. This is a form of federalism, I suppose, cognizant of the different values and choices of legislatures and voters in different states.