CHICAGO - We all know that well-intended laws can have unintended consequences. When the federal government capped the price of oil, gas got more expensive. When it raises the minimum wage, people who used to get a lousy wage often find themselves out of a job, making a wage of zero. As economist Milton Friedman once said, if you put the government in charge of the Sahara, there would soon be a shortage of sand.
So it's not hard to believe an argument that has gained currency lately: When we raised the drinking age from 18 to 21, we didn't solve the problem of irresponsible alcohol consumption by young people - we made it worse.
August Busch III, chairman of Anheuser-Busch, has said the higher drinking age "results in the very behavior we are trying to fight." Barrett Seaman, author of the book Binge: What Your College Student Won't Tell You, blames the higher drinking age for the alarming number of college students who end up hospitalized or dead from alcohol poisoning.
Writing in Time magazine, Mr. Seaman says that in Montreal, where 18-year-olds may drink, students are less likely to end the evening hugging a toilet. His remedy: Roll back the drinking age so youngsters can drink in legal, controlled settings and "learn to handle alcohol like the adults we hope and expect them to be."
This is an elegant, provocative theory. It also dovetails with the common-sense notion that there's something unfair and irrational about regarding 18-year-olds as adults when it comes to voting or enlisting in the military but treating them like middle-schoolers when it comes to drinking. The whole line of argument is perfect, except for one thing: It's about two solar systems away from reality.
As it happens, there is a mountain of evidence on the effects of raising the drinking age. It all shows that the change had no ill effects and, in fact, did an immense amount of good. To start with, barring alcohol sales to those under 21 didn't cause an epidemic of drunkenness among those who lost their privileges.
Monitoring the Future, which conducts annual surveys of attitudes and behavior among young people, says that in 1984, when the federal government mandated a drinking age of 21, 45.4 percent of college students engaged in binge drinking, defined as five or more drinks in a row in any given two-week period. By 2003, only 38.5 percent did so.
The number of students who drink every day, meanwhile, has fallen by a third, while the number of students who abstain in any given month has risen by 61 percent. When we banned drinking by those ages 18 to 21, they drank less. Sometimes, laws don't have unintended consequences - they have intended ones.
High school seniors are far less likely to engage in binge drinking than they were in the days when 18-year-olds could legally buy beer, even though more than 90 percent say alcohol is still easy to get.
Drinking and driving used to be the leading cause of death among teenagers, but no more. In 1984, more than 10,000 drinking drivers under the age of 21 were involved in fatal crashes. By 2003, the number was down to 8,035.
The National Highway Traffic Safety Administration estimates that the higher drinking age saves more than 900 lives every year. Since 1984, some 18,000 lives have been spared.
When government policies defeat their own purposes, they deserve to be repealed. But lowering the drinking age to curb alcohol abuse is like trying to reduce crime by disbanding the police.
Steve Chapman is a columnist for the Chicago Tribune, a Tribune Publishing newspaper. His column appears Mondays and Wednesdays in The Sun.