America culturally is very diverse, and varies greatly from state to state. When a policy seems oddly uniform across all the states, it's likely due to a Supre

America culturally is very diverse, and varies greatly from state to state. When a policy seems oddly uniform across all the states, it's likely due to a Supreme Court ruling or federal legislation. In the case of minimum drinking ages, it's a need for federal highway money that's alive and well in the United States - in 1984, Ronald Reagan tied receiving the full portion of federal funds for infrastructure to having a minimum drinking age of 21. Prior to that, minimum drinking ages varied from 18 to 21 depending on the state - each state set its own social policy, which in my opinion is how it should be. Digging deeper into the issue, you can see how certain states resisted raising their drinking age, despite funding implications - Wyoming took several years to raise their drinking age, and Louisiana had a loophole that made it illegal buy alcohol but not illegal to sell it until the mid-1990s. On the PATH, a commuter train from New Jersey to New York, there are public service ads from Mothers Against Drunk Driving against lowering the drinking age, since deaths from drunk driving have dropped dramatically since 1984. Whenever I see one, I get the urge to scribble 'correlation is not causation' on it.