Findlaw columnist Barton Aronson has a thoughtful article here, which is hard to disagree with.
In Conant v. Walters, the Ninth Circuit barred the government from prosecuting doctors who merely inform patients about the benefits of medical marijuana. The Justice Department is appealing that ruling to the Supreme Court.
Aronson poses a question and then answers it for us:
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.
I think that Aronson's analysis is correct, and that the Supreme Court would have a difficult time ruling otherwise.