since the 21st amendment repealed nationwide prohibition in the united states, alcohol prohibition legislation has been left to the discretion of each state, but that authority is not absolute. states within the united states and other sovereign territories were once assumed to have the authority to regulate commerce with respect to alcohol traveling to, from, or through their jurisdictions. however, one state's ban on alcohol may not impede interstate commerce between states that permit it. the supreme court of the united states held in "granholm v. heald" that states do not have the power to regulate interstate shipments of alcoholic beverages. therefore, it may be likely that municipal, county, or state legislation banning possession of alcoholic beverages by passengers of vehicles operating in interstate commerce (such as trains and interstate bus lines) would be unconstitutional if passengers on such vehicles were simply passing through the area. following two 1972 raids on amtrak trains in kansas and oklahoma, then dry states, the bars on trains passing through the two states closed for the duration of the transit, but the alcohol stayed on board.