You probably wouldn't do that, right?
Yet this is what we do with alcohol. You can be 20 years and 364 days old and it is still illegal for you to drink. In fact, if you did drink, you were breaking the law and so was anybody else that provided you with alcoholic beverages - including your own parents. Yet the very next day, on your 21st birthday, you can now legally walk into a bar and drink yourself under the table.
What sense does that make?
Can somebody explain?
One could just as easily say, "You can be 17 years and 364 days old and it is still illegal for you to star in a porn movie. In fact, if you did, you were breaking the law and so was anybody else who was making the movie with you. Yet the very next day, on your 18th birthday, you can now legally walk into a bedroom and have all the sex the camera can capture. What sense does that make?"
A society that proscribes children engaging in certain activities is compelled to draw an arbitrary line. When the line is drawn, there will be those on one side of the line who perhaps should be able to engage in the activity, but can't, and those on the other side of the line who should not be able to engage in the activity, but can. There are 12-year-olds who could responsibly drink wine at the dinner table, and 30-, 40-, 50-, and 60-year-olds who should never touch the stuff. A society of virtuous people would not need a government drawing the line, but if we were ever a society of virtuous people, we have long since lost that distinction.
Push the drinking age back to 18, and around 2,000 people annually will die in teen DUI accidents who are not dying now, based on how many died before the age was raised to 21. OTOH, a few hundred million dollars will not be spent on underage-drinking enforcement that is being spent now. If we wanted to, and were willing to use whatever means were necessary, we could use that money to essentially rid Africa of malaria, or rid India of cholera, and save many more than 2,000 lives--but that would require first the willingness to say that lives in Africa and India are as worthwhile as those in the US, second the willingness to allow older teens to live, or die, with the consequences of their own, sometimes immature choices, and third the ensuring that the money saved from the non-enforcement of "21" would actually go into effective programs to save those who are in danger of malaria or cholera. Those are three big "if"s, and if a society is not virtuous enough to handle individual choice in alcohol, it certainly would not be virtuous enough to handle the three "if"s.
If anything these laws make people less responsible in their drinking. This taboo attitude prevents the most important part of being a responsible drinker: practice. Drinking is like anything else we do with/ to our body, the only way to learn to do it to do it. You can’t learn how alcohol effects your judgement and co-ordination sober, you can’t learn how your body dries out without giving it something to dry out, you can’t learn the difference in effect of drinking with food or without without drinking. If we really want responsible drinkers then we need to start them drinking younger not older, phase them into it, demystify, with adult supervision. The places that culturally encourage mild drinking (the ever popular wine with dinner) in the family circle have a lot fewer problems. Of course it also doesn’t help that our drivers licenses come out of cracker jack boxes, but that’s a whole other rant.