August 1996: Federal drug czar Barry McCaffrey tells the San Francisco Chronicle "there is not a shred of scientific evidence that shows that smoked marijuana is useful or needed," adding, "This is not medicine. This is a cruel hoax."

December 1996: Asked whether there is "any evidence...that marijuana is useful in a medical situation," McCaffrey says, "No, none at all."

February 2001: The U.S. Department of Health and Human Services files a patent application for the medical use of cannabinoids, saying they are "useful in the treatment and prophylaxis of wide variety of oxidation associated diseases, such as ischemic, age-related, inflammatory and
autoimmune diseases," and "are found to have particular application as neuroprotectants, for example in limiting neurological damage following ischemic insults, such as stroke and trauma, or in the treatment of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease and HIV dementia."

October 2003: The patent is granted.

April 2006: The Food and Drug Administration says an "evaluation by several Department of Health and Human Services (HHS) agencies...concluded that no sound scientific studies supported medical use of marijuana for treatment in the United States, and no animal or human data supported the safety or efficacy of marijuana for general medical use."

July 2008: The Drug Enforcement Administration says "marijuana has no medical value that can't be met more effectively by legal drugs."

What's going on here? The government wants to draw a distinction between whole-plant marijuana, which it insists has "no currently accepted medical use," and marijuana ingredients, including THC and cannabidiol, that have demonstrated medical utility. As drug czar John Walters put it in an "Ask the White House" Q&A last December:

We believe that if there are elements of marijuana that can be applied to modern medicine, they should undergo the same FDA-approval process any other medicine goes through to make sure it's safe and effective. In absence of that approval, the Federal position is clear: the smoked form of medical marijuana is against Federal law and we will continue to enforce the law.

According to Walters, while it is emphatically forbidden, and not at all helpful, to smoke, vaporize, or eat cannabis as a medicine, it may be acceptable to take isolated cannabinoids as a medicine once they're approved by the FDA, assuming you have a prescription. The FDA already has approved THC (in capsule form) under the brand name Marinol, and it is considering approval of Sativex, an oral cannabis extract spray. At the same time, the government does not want people to believe that anything good could possibly come from cannabis, even when it has successfully argued that very point in its own a patent application.

[Thanks to NORML's Paul Armentano for the patent tip.]