Age limits never stopped any kid from obtaining cigarettes and liquor.
Ask any smoker--most start in junior high.
So imposing an age restriction isn't working. How is raising it even higher going to make any difference?
Well it does. The Journal of Studies on Alcohol and Drugs has many studies showing that it does
There was a study by the Insurance Institute for Highway Safety on the drinking age change from 18 in most states, to mandatory 21 federally in 1988.. Among fatally injured drivers ages 16-20, the percentage with positive BACs declined from 61% in 1982 to 31% in 1995, a bigger decline than for older age groups; declines occurred among the ages directly affected by raising MLDAs (ages 18-20) and among young teenagers not directly affected (ages 16-17). Almost all studies designed specifically to gauge the effects of drinking age changes show MLDAs of 21 reduce drinking, problematic drinking, suicide rates, drinking and driving, and alcohol-related crashes among young people.
Another in the Journal of Economic Perspectives put a dollar figure on those changes post MLDA, and figured based on the cost of life for the increased mortality, and taking drinking rates of those in that age group, each drink would cost another $15 to the drinker, and $2.50 to the general public by the increased deaths.
I think stronger enforcement helps. When I was a kid, I can think of more than one time getting busted with alcohol by the police and not getting a ticket but rather a warning. A couple times even allowed to keep what I had. I knew a store where we'd go and he'd ask for ID and if we didn't have it, rather than putting it in the paper bag, he'd put it in his plastic regular grocery bags and charge us an extra couple bucks. I remember he bumped the price he said to pay for his underage selling ticket he got once.
Lastly pushing parents to actually.... parent. I think more holding of parents accountable for kids in the house at least. Not the fine and charges (unless they are there holding the party or buying the alcohol), but forcing them to go through the classes and community service too.
That said I also agree with the "if you are old enough to serve, you are old enough to drink and smoke".