Gonna go against the grain and say 21 for the US.
Raising the drinking age had a direct effect on reducing car accidents. The problem is that you are not just endangering yourself, you're endangering others. To prove the phenomenon is not unique to the US,
Canada which has a comparable inelastic demand of driving to get around shows a similar problem of provinces with a drinking age of 19 having a lower mortality than that of 18.Now in Europe where public transit's a lot better? 16 for brews/wine and 18 for spirits. I'd support a similar age here if we had the infrastructure for it. Granted, I probably drank more in high school than I have since turning 18 let alone since 21 so you tell me how effective bans are period. Raiding your parents liquor cabinet or getting an older friend who has a fake to buy brews is a rite of passage.
I voted for 18. It's beyond ridiculous to say someone is mature enough to join the military, where they'll handle and potentially use deadly weapons that could--and do--get innocent people killed, yet not mature enough to be responsible regarding drinking and driving.
The only reason it's not 18 is that politicians haven't had the balls to stand up to groups like Mother's Against Drunk Driving and say: "Yes, what happened to your child was tragic, but having the drinking age be 21 is not an appropriate reponse. An 18 year old can kill someone if they drink and drive, but so can a 21 year old or an 81 year old. And someone killed by the latter two is just as dead as someone killed by the first."
Is there any evidence that 18-21 year olds are more likely to misuse firearms like there is statistically significant evidence for them to have car accidents? Also where in the Constitution is there a right to drink?