THE CAMPAIGN to legalize the medical use of marijuana has organized eight ballot initiatives over the past three years. The Clinton administration has opposed all of them, and all have passed. The latest test came in Maine on Tuesday. Barry McCaffrey, President Clinton's drug czar, urged a no vote. But a large majority said yes.

The administration fears that permitting marijuana to alleviate the pain of AIDS and cancer may open the way to more general legalization. It worries that saying yes to medical marijuana will muddy public education efforts that denounce drug use. Moreover, referendums seem an odd way to make decisions that properly belong to doctors and health regulators.

All these arguments have some merit, yet none is overwhelming. Medical use of marijuana cannot be said to lead inevitably to drug legalization or a pro-drug culture. Referendums can be haphazard, but voters are not the only group supporting medical marijuana. Earlier this year the Institute of Medicine concluded that marijuana-derived chemicals can alleviate cancer and AIDS symptoms; it added that these chemicals would be best delivered in a non-smoked form.

Moreover, the danger that medical marijuana would undermine the broader anti-drug effort is receding. The first ballot initiative that passed, in California, was flawed: Marijuana clubs sprouted, and police complained that some members were not in genuine medical need. Since then, ballot initiatives have been drafted so as to control access, and the drafters have accepted further restrictions after their measures won approval in referendums.

It is time for the administration to drop its doctrinaire opposition to medical marijuana. It is ineffective and unpopular--both with voters and with some law enforcers. Rather than harass doctors who prescribe marijuana, the administration should reopen the federal program under which, until 1991, marijuana was available to terminally ill patients.