BOSTON -- I don't know when the town drunk was officially transformed into a victim of alcoholism. It is still only 30 years since the American Medical Association first declared that chronic drunkenness wasn't a sin. It was, rather, a disease.

Now, according to polls, some 87 percent of us accept alcoholism as a sickness. But our attitudes toward the ''ism'' of alcohol are not as clear as this figure suggests.

We may no longer want to condemn alcoholics for their addiction. On the other hand, we don't want to excuse them from responsibility for their behavior.

This ambivalence about the semantics and social policy of alcohol abuse is now coming before the Supreme Court. Next week, the high court will hear the cases of two men, both veterans, both recovered alcoholics, both suing the Veterans Administration.

The two men missed the VA deadline for college benefits. They were drunk during their eligible years. They complain that under the VA guidelines, disabled veterans would have had longer to apply for these benefits. But the VA doesn't call alcoholism a disability. It calls alcoholism ''willful misconduct.'' So these two have accused the VA of illegally discriminating against them on the basis of their handicap: alcoholism.

The case may finally turn on some minor point, but it raises major questions. Is alcoholism a disease? Is an alcoholic disabled in the sense that, say, a paraplegic is? Does he deserve an extra hand from society, an extension of benefits, a special ramp into life? Must we then agree that alcoholism is a legitimate excuse for misbehavior, even for a crime?

In a curiously parallel case, the president's friend, Michael Deaver, is using alcoholism as a defense against charges of perjury. He was too sick to know what he was saying. The disease, not the man, done it.

These lines between sick behavior and bad behavior are not always clear. Leonard Glantz of Boston University's School of Public Health offers another example: ''If you have a brain tumor and attack me because of this tumor, is it fair to send you to jail? Most people would think not. But if you ran me down with a car because you were in the throes of alcoholic delusion, should you go to jail? Most people would say yes.''

Our ambivalence toward alcoholism may be entirely appropriate, even accurate. We are often comfortable labeling alcoholism as a disease. There is medical evidence to match the terminology. We know alcohol can be addictive. We read that people can inherit a susceptibility to addiction. There may be a genetic link.

The semantics also fit our current social-policy desires. If alcoholics are ''sick'' instead of bad, they need, indeed deserve, help. This attitude has destigmatized the addiction, and put into place a vast array of programs on alcohol abuse.

At the same time, we know that alcoholism has an element of choice. You can't just say no to cancer. But you can say no to a drink. The cure is not in the hands of a surgeon. It is in the hands of the ''victim.'' Indeed part of the cure is getting people to take responsibility for their actions.

Ultimately, says Glantz, ''we still must make choices about how people are handled.'' Choices for the whole of society, not just a 'sick' individual. Most of those choices are made in the courts, not the medical lab. Today, even a sociopath -- someone who has no regard for the life of others -- is not considered mentally ill for the purposes of criminal prosecution.

We can label alcoholism a disease to help those who are in need. But we shouldn't accept it as a defense, when the alcoholic's behavior threatens the rest of the community.

If Michael Deaver had blacked out on the highway and slammed into another car, we would not have forgiven his behavior on account of drunkenness. Nor should we forgive perjury on these grounds.

As for the veterans demanding their handicapped rights, I don't think we should extend to alcoholics benefits that are denied to the sober. Remember that these two veterans have recovered from their disease. They didn't do it by making excuses.