The Justice Department has decided that criminalizing marijuana - a perfectly defensible position - also requires criminalizing talking about marijuana. That's the upshot of the decision to appeal the ruling of the U.S. Court of Appeals for the Ninth Circuit in Conant v. Walters, which barred the government from prosecuting doctors who inform patients about the benefits of medical marijuana.

Federal policy on medical marijuana has grown more inflexible even as the scientific community's view of its efficacy grows more fluid. Marijuana, like other controlled substances, is available only in tightly regulated situations. The government still funds some clinical trials for cannabis, but that's about it; the guy on the corner selling weed in dime bags is probably not covered by a federal grant.

In the mid-1990s, several states passed laws permitting doctors to prescribe marijuana to patients for whom other treatments had failed. In response, the Clinton Administration issued regulations clarifying that there were no exceptions in the federal drug laws for medical use of marijuana, and threatening doctors who prescribed it with revocation of their license to prescribe drugs.

That policy was upheld by the U.S. Supreme Court two years ago in United States v. Oakland Cannabis Buyers' Coop. The doctors behind the Conant case do not challenge that result.

But the federal response to the state medical marijuana laws also included a gag order, first sought by the Clinton Administration, that is the subject of Conant. The gag rule was in the form of regulations barring doctors from even recommending marijuana to their patients, even if the doctors made no effort to prescribe. A federal district court immediately enjoined enforcement of that part of the law, and the Clinton Administration was content to let matters lie.

Meanwhile, in 1999, the National Institute of Medicine of the National Academy of Sciences released its two year long study of the issue, undertaken at the request of the White House. It concluded that marijuana had therapeutic value, and that for some fraction of patients, marijuana was superior to other available treatments.

Fast forward to the present. Recently, the judge who entered the original injunction against the gag rule decided to make it permanent. The Justice Department appealed to the Ninth Circuit - and lost. Now the Justice Department is taking the case to the Supreme Court.

Why the Medical Marijuana gag Rule Violates the First Amendment

Conant does not involve doctors who prescribed marijuana. It doesn't involve doctors who grew it or gave it away. At issue is simply the right of doctors to say - and patients to hear - something nice about the medical use of cannabis.

While the First Amendment looks askance at most restrictions on speech, this particular regulation is a three-time loser - a viewpoint based restriction on professional speech implicating a matter of intense public interest.

The law is a viewpoint-based restriction because it punishes only doctors who recommend medical marijuana - that is, who tell patients marijuana might be good for them. It does not punish doctors who disparage marijuana as a course of treatment.

But the government is not supposed to tell us what to think, which is why the law is so hostile to restrictions on speech keyed to the viewpoint expressed by the speaker. In a marketplace of ideas, such restrictions are the equivalent of price controls. The government isn't supposed to set the value attached to ideas, though; that's our job, and under the First Amendment, our right.

The law is also troubling because it interferes with a patient's right to hear what her doctor has to say. The courts are highly solicitous of our right to seek advice from professionals. Recently, in Legal Services Corp. v. Velazquez, the Supreme Court struck down a law barring lawyers in federally funded legal clinics from advising welfare recipients about challenges to the welfare laws.

These rights are no less urgent when it comes to medical professionals, and maybe even more so. Courts have long recognized the importance of the doctor-patient relationship. While the government protects our health by regulating available courses of treatment, courts have traditionally refused to interfere in what doctors and patients say to one another, and will not assume, when reviewing such regulations, that doctors will give medically unsound advice or that patients need to be protected from what a medical professional views as the truth.

The law is particularly quixotic given the government's continued conduct of clinical trials involving marijuana. Under the policy, a doctor could probably be punished for telling a patient about the mere existence of such trials. Surely the Department of Justice will not be prosecuting those who administer grants for the Department of Health and Human Services.

Why the Justice Department's Defense of the Law is Unconvincing

In the teeth of all this First Amendment law, the Justice Department has defended its position by arguing that a doctor's advice about medical marijuana may just motivate someone to try to get his hands on some marijuana - in other words, to break the law.

Obviously, doctors are not allowed to conspire with or aid and abet their patients in getting marijuana, but all of that is already illegal. This policy is aimed at something short of that - a doctor who simply tells a patient, "marijuana would help."

That statement could, conceivably, motivate someone to go out and buy marijuana. It could also motivate him to write his congresswoman, sign a petition, or take out a subscription to High Times. None of these results is any more likely than the other, and most of them are not only legal, but at the core of what the First Amendment protects - expressive activity about matters of public concern, which is exactly what the medical use of marijuana is.

The mere possibility that a patient would go out and buy marijuana doesn't even approach the exacting legal standards for criminalizing speech. The government is allowed to restrict speech when it is likely to lead to illegal conduct, but the connection - between speech by one and action by another - must be very, very close. The old formulation required that the speech present a "clear and present danger" - something akin to shouting "attack!" to an already angry mob.

While the law in this areas has been refined, it has not really changed. If the government wants to limit speech because it may incite crime, then the speech must be intended to do so and be very likely to, imminently, not at some undefined point in the future. The fact that a doctor's statement about the efficacy of marijuana may lead a patient to try to secure some is not a set of facts remotely similar to those rare situations in which this has served as a permissible basis for squelching speech.

In light of current law, it is nearly impossible to imagine a Supreme Court opinion faithful to our First Amendment jurisprudence that would leave in place the government's gag order on doctors' speech regarding medical marijuana. Such circumstances call for restraint - not only by the judicial branch, but by the executive branch that appears before it.