George Will writes against the federal mandate of a 21 year-old drinking age. I think Will actually left out the worst part of these rules, which is that they've created a cottage industry of fake IDs whose main purpose is to let teenagers procure beer. Since nobody thinks that teenagers buying beer is an especially serious offense, enforcement of the laws against production of such fake IDs is pretty lax. Accurate identification is, however, an important element of general law enforcement and counterterrorism. It would be very helpful for law enforcement if one could assume that fake IDs were generally being for something genuinely problematic and worth looking in to.
The best way to reduce drunk driving would be to have more people live in high-density areas well-served by taxis and mass transit, though we're presumably not going to implement such a scheme in the short-term.