LAST WEEK, the Cambridge City Council passed a "home rule" petition that would make prescription marijuana available for medicinal purposes within the city. The petition officially asks the Massachusetts state legislature to authorize Cambridge to take advantage of a now-defunct FDA program which granted medicinal marijuana to the desperately ill.

The petition is falling upon deaf ears. Massachusetts is one of 16 states in the nation that bans marijuana for any and all purposes. And in the black-and-white world of drug enforcement policy, the federal government does not take kindly to subtle shades of gray. (Never mind that cocaine and morphine--two of the biggest targets of the War on Drugs--have been available by prescription for years.)

So the Cambridge resolution is both futile and irrelevant. Right? Well, it certainly is futile (it falls under the same heading as an Undergraduate Council resolution on human rights in China).

But the petition need not be seen as irrelevant. In fact, the resolution serves to emphasize the important medical and ethical arguments in favor of legalizing medicinal marijuana. But perhaps more importantly, the council's stand demonstrates that, although the medicinal marijuana movement has long been associated with the burntout pot smokers of the '60s, the time has come for mainstream America to embrace the cause.

THE THERAPEUTIC EFFECTS of cannabis have been known since ancient times, but are still not completely understood. What we do understand is that marijuana is effective in treaticng glaucoma, multiple sclerosis, chemotherapy-induced nausea and, now, loss of apetite in cases of AIDS.

The federal government understands this too, and in 1985 made available by prescription a synthetic version of THC, the active ingredient in pot. What's at issue now is the right of doctors to prescribe marijuana in smoked form. So. you may ask, if there's a pill that's just as good, why do those nasty, smelly little cigarettes need to be legal too?

Numerous scientifically valid studies have shown that marijuana in smoked form can be more medically effective than purified THC. Most recently, a 1988 study in The New York State Journal of Medicine showed that 29 percent of those who did not respond to oral THC did respond to smoked marijuana.

Furthermore, one of the DEA's tests of whether a drug should be available by prescription asks whether it has "currently accepted medical use." A current study by Kennedy School Lecturer Mark A.R. Kleiman showed that 54 percent of surveyed oncologists thought smoked marijuana should be available by prescription. Forty-four percent said they had already recommended pot to a patient.

The medical reasoning is sound. The legal reasoning is sound. But, hung up on an age-old taboo against "herbal medicine," overzealous government drug-warriors are unwilling to forfeit their "Just Say No" mantra for the wimpy-sounding Just Say Sometimes. That's the reasoning that led to the discontinuation of the FDA's "compassionate approval" program. And that's the reasoning that's keeping one of the few effective appetite enhancers away from dying AIDS patients.

CLEARLY, the Cambridge City Council cannot undercut the authority of the Drug Enforcement Agency on this one. At best, we can hope that the resolution sends a defiant message to our state and federal officials. But the real value of the resolution lies not in what it says, but in who said it.

The movement for medicinal marijuana has been around since the '60s, but its supporters have usually been those who also supported legalized marijuana, and legalized LSD and legalized glue sniffing. In the 1970s and earlier '80s, medicinal marijuana gained support from many doctors, but it was too late--the movement was inextricably associated with a lunatic fringe of burnt-out hippies making their last pathetic effort to salvage the '60s. In the Reagan-Bush years, that kind of coalition just doesn't float.

The seven city councillors who voted for this week's resolution did a courageous--and sensible--thing. They lent their names, and the name of their city, to a humane and worthy cause too often written off because of strange bedfellows. Granted, such a resolution may not mean much coming from the city that much of America knows as Moscow on the Charles.

But it is a step in the right direction. If the medicinal marijuana movement is to succeed, it needs to win over not only the medicinal community, but the political community as well. And even if the city council does not convince the feds, or the state, or anyone else, to legalize prescription pot, it is at least sending the right message: Medicinal marijuana--it's not just for hippies anymore.