It's been 20 years that America has had a minimum federal drinking age. The policy began to gain momentum in the early 1980s, when the increasingly influential Mothers Against Drunk Driving added the federal minimum drinking age to its legislative agenda. By 1984, it had won over a majority of the Congress.

President Reagan initially opposed the law on federalism grounds but eventually was persuaded by his transportation secretary at the time, now-Sen. Elizabeth Dole.

Over the next three years every state had to choose between adopting the standard or forgoing federal highway funding; most complied. A few held out until the deadline, including Vermont, which fought the law all the way to the U.S. Supreme Court (and lost).

Twenty years later, the drawbacks of the legislation are the same as they were when it was passed.

The first is that the age set by the legislation is basically arbitrary. The U.S. has the highest drinking age in the world (a title it shares with Indonesia, Mongolia, Palau). The vast majority of the rest of the world sets the minimum age at 17 or 16 or has no minimum age at all.

Supporters of the federal minimum argue that the human brain continues developing until at least the age of 21.

Alcohol expert Dr. David Hanson of the State University of New York at Potsdam argues such
assertions reek of junk science. They're extrapolated from a study on lab mice, he explains, as well as from a small sample of actual humans already dependent on alcohol or drugs. Neither is enough to make broad proclamations about the entire population.

If the research on brain development is true, the U.S. seems to be the only country to have caught on to it.

Oddly enough, high school students in much of the rest of the developed world — where lower drinking ages and laxer enforcement reign — do considerably better than U.S. students on standardized tests.

The second drawback of the federal drinking age is that it set the stage for tying federal mandates to highway funds, enabling Congress to meddle in all sorts of state and local affairs it has no business attempting to regulate — so long as it can make a tortured argument about highway safety.

Efforts to set national speed limits, seat belt laws, motorcycle helmet laws and set a national blood-alcohol standard for DWI cases have rested on the premise that the federal government can blackmail the states with threats to cut off funding.

The final drawback is pretty straightforward: It makes little sense that America considers an 18-year-old mature enough to marry, to sign a contract, to vote and to fight and die for his country, but not mature enough to decide whether or not to have a beer.

So for all of those drawbacks, has the law worked? Supporters seem to think so. Their primary argument is the dramatic drop in the number of alcohol-related traffic fatalities since the minimum age first passed Congress in 1984. They also cite relative drops in the percentage of underage drinkers before and after the law went into effect.

But a new chorus is emerging to challenge the conventional wisdom. The most vocal of these critics is John McCardell Jr., the former president of Middlebury College in Vermont. McCardell's experience in higher education revealed to him that the federal age simply wasn't working.

It may have negligibly reduced total underage consumption, but those who did consume were much more likely to do so behind closed doors and to drink to excess in the short time they had access to alcohol. McCardell recently started the organization Choose Responsibility, which advocates moving the drinking age back to 18.

McCardell explains that the drop in highway fatalities often cited by supporters of the 21 minimum age actually began in the late 1970s, well before the federal drinking age set in.

What's more, McCardell recently explained in an online chat for the "Chronicle of Higher Education," the drop is better explained by safer and better built cars, increased seat belt use and increasing awareness of the dangers of drunken driving than in a federal standard.

The age at highest risk for an alcohol-related auto fatality is 21, followed by 22 and 23, an indication that delaying first exposure to alcohol until young adults are away from home may not be the best way to introduce them to drink.

McCardell isn't alone. Kenyon College President S. Georgia Nugent has expressed frustration with the law, particularly in 2005 after the alcohol-related death of a Kenyon student. And former Time magazine editor and higher ed reporter Barrett Seaman echoed McCardell's concerns in 2005.

The period since the 21 minimum drinking age took effect has been "marked by a shift from beer to hard liquor," Seaman wrote in Time, "consumed not in large social settings, since that was now illegal, but furtively and dangerously in students' residences. In my reporting at colleges around the country, I did not meet any presidents or deans who felt the 21-year age minimum helps their efforts to curb the abuse of alcohol on their campuses."

The federal drinking age has become somewhat sacrosanct among public health activists, who've consistently relied on the accident data to quell debate over the law's merits.

They've moved on to other battles, such as scolding parents for giving their own kids a taste of alcohol before the age of 21 or attacking the alcohol industry for advertising during sporting events or in magazines aimed at adults that are sometimes read by people under the age of 21.

But after 20 years, perhaps it's time to take a second look—a sound, sober (pardon the pun), science-based look—at the law's costs and benefits, as well as the sound philosophical objections to it.

McCardell provides a welcome voice in a debate too often dominated by hysterics. But beyond McCardell, Congress should really consider abandoning the federal minimum altogether, or at least the federal funding blackmail that gives it teeth.

State and local governments are far better at passing laws that reflect the values, morals and habits of their communities.

Radley Balko is a senior editor for reason. This article originally appeared at FoxNews.com.

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