Alcoholism and alcohol-related crimes are far too common in the United States. The solution to the problem is not prohibition. However, outright legalization of alcohol sale and use based on age is also insufficient.
Alcohol sale and use should be regulated by a licensing system that is similar to that in place for granting and maintaining driving privelages. Those who prove themselves able to responsibly sell, purchase, and use alcohol should have the freedom to do so. Those who do not prove themselves responsible should have these privelages denied.
The financial costs of emplacing this system are relatively small given that age-verification is already a major part of the alcohol regulatory process. Many lives will be saved by denying access to repeat DUI offenders and the like.