When there's a dispute about stuff on this board, there is also a lot of throwing around of statistics. I don't really listen to them, as they are usually manipulated, by whatever agency is publishing the results, to the point where there's little meaning. So, those statistics mean nothing to me. With that in mind, I believe the underage drinking problems, and alcohol-related health problems are still WORSE here in the good old U.S.A. than in Europe. Most of it is our Puritan heritage, like someone said. In Italy, there is no "drinking" age. If two 14-year olds order wine with dinner, they get wine with dinner. No biggie. Usually, the server will monitor their behavior, but that's up to the server. But, when I went out, which was about 3 times/week, who did I see puking behind the bushes, being generally loud and obnoxious and embarassing? AMERICAN COLLEGE STUDENTS, that's whom!
In response to the "I can die for my country" argument...the keys to the world aren't handed to you at the age of 18. In most cases, you are given more LEGAL accountability for your behavior, but you don't have a lot of the same economic and social priveleges that are afforded to someone slightly younger.
The drinking age is fine where it is. I say that as someone who grew up knowing how to drink responsibly, but saw the consequences of alcohol abuse. I don't think I would have had any more or less to drink on my 18th birthday as I did on my 21st if it had been legal, 'cause at that point drinking wasn't that big a deal. I do have HS classmates, however, whose parents were anti-alcohol, and most of them got booted from college after frosh year due to their alcohol use/bad grades. Oh well.