A consortium of college presidents under the auspices of the Amethyst Initiative is questioning whether the 21-year-old national drinking age works. They claim it contributes to binge drinking, a destructive force on college campuses. What the group is looking for is removal of the teeth in the 1984 National Minimum Drinking Age Act, which essentially robs any state that doesn't fall in line with an end to its federal highway funding. With the federal limitation removed, they say, states would be free to allow the purchase of alcohol by 18-, 19- and 20-year-olds. Proponents of the movement have said the problem with the 21-year-old drinking age is that if college counselors detect a drinking problem with a younger college student they are powerless to do anything about it - because they can't suggest more appropriate levels of drinking when the activity itself is against the law. Many in Illinois remember when Wisconsin had a lower drinking age. Teens streamed across the border to drink, then drove back home. Many never made it and the state line became known as ''Blood Border.'' There are some things 18-year-olds - college or not - just aren't mature enough to deal with. The fact that alcohol is illegal for 18-year-olds to consume does not absolve colleges from taking steps to inform teens of the dangers of alcohol abuse. We view their argument as a cop-out.