Nine years ago, supporters of medical marijuana asked the federal government to reclassify cannabis, which was listed as a Schedule I drug, the most restricted category of drug under the Controlled Substances Act in 1970. The petition asked the the U.S. Drug Enforcement Administration (DEA) to take into account research showing marijuana's medical uses, which have been recognized in various states and the capital. For years, no final decision was reached, the Los Angeles Times reports. Two months ago, advocates asked the U.S. Court of Appeals to force the Obama administration to respond to their petition. Finally, in a decision published Friday, the DEA denied the request, ruling that marijuana has no accepted medical use and should remain classified as a highly dangerous drug like heroin.

DEA Administrator Michele M. Leonhart wrote that she rejected the request because marijuana, like other Schedule I drugs, "has a high potential for abuse," "has no currently accepted medical use in treatment in the United States," and "lacks accepted safety for use under medical supervision." She wrote that "At this time, the known risks of marijuana use have not been shown to be outweighed by specific benefits in well-controlled clinical trials that scientifically evaluate safety and efficacy."

At the outset, this seems like a major blow for the fight to legalize marijuana. Who (or what) has the most to lose?

Science. Perhaps most notable about the decision, even taking into account the DEA's careful language, is that it attacks the popular belief that the medical benefits of marijuana are long established. Synthetic forms of marijuana, for one, are federally approved in treating conditions like glaucoma. Neuropsychiatrist Dr. Igor Grant, director of the Center for Medicinal Cannabis Research at UC San Diego, told the LA Times that state-supported clinical trials show that marijuana helps with neuropathic pain and muscle spasticity. Joe Elford, chief counsel for Americans for Safe Access, noted that studies demonstrate pot stimulates the appetite for people undergoing chemotherapy. But more research needs to be done. In 2009, the American Medical Assn. urged the government to review its classification of marijuana "with the goal of facilitating the conduct of clinical research and development of cannabinoid-based medicines, and alternate delivery methods." Thus, there is fear that this latest ruling may hinder medical research for some time to come.

State law. When the petition was originally filed, eight states had approved medical marijuana. Now 16 states and the District of Columbia have joined in. Will users of medical marijuana continue to be protected by their states' laws? That issue is also becoming less clear. In the recent past, the federal stance on marijuana was not a threat to legal users under state law. In an October 2009 memo to U.S. attorneys, Deputy Attorney General David Ogden instructed that they "should not focus federal resources" on "individuals whose actions are in clear and unambiguous compliance with existing state laws providing for the medical use of marijuana." But late last month Ogden's successor James Cole issued a new policy that "commercial operations cultivating, selling or distributing marijuana" are, in the words of Jacob Sullman at Reason, "fair game, even when they are explicitly authorized by state law." Sullman describes:

The new memo even suggests that state employees could be prosecuted for licensing and regulating dispensaries, saying people "who knowingly facilitate" the distribution of medical marijuana "are in violation of  the Controlled Substances Act, regardless of  state law," and "are subject to federal enforcement action, including potential prosecution."

In light of this recent finding by the DEA, the federal government has only strengthened its disparate position from many states.

Federal law. On a federal level, however, this ruling is not all bad news for marijuana advocates. According to chief counsel Elford, the government was employing a "strategy of delay" these past nine years, and, now that it has come out on one side, advocates can finally appeal, enabling them to "go head-to-head on the merits." However, it should be noted that the two times when petitions to reclassify marijuana failed in the past, first in 1972 and then in 1995, the courts sided with the federal government on the appeal. 

Politics. The Obama administration has been clearly identified as a barrier in the fight to legalize marijuana. The recent ruling " is clearly motivated by a political decision that is anti-marijuana," Elford said. Sullman puts the administration into context and expresses his disappointment:

[T]he position that Obama is now taking on medical marijuana—go after producers and sellers but leave patients alone—is no different from the position his predecessor took. In fact, Obama's crackdown on medical marijuana is, if anything, more aggressive than Bush's, with more frequent raids, IRS audits that threaten to put dispensaries out of business, forfeiture threats to dispensaries' landlords, and direct interference in the legislative process by U.S. attorneys. This is certainly not what voters thought they were getting when they heard Obama repeatedly promise to change course on this issue.

But how much can this affect Obama's political popularity? Although support for the legalization of marijuana has been rising, there is still no clear majority of opinion nationally. In a poll conducted last March by the Pew Research Center, 45 percent of adults supported legalization while 50 percent were against it. However, the poll did not take into account legalization of medical marijuana, which typically yields higher levels of support. Moreover, a majority of independent voters (who Obama will be seeking to curry favor with) were in favor of legalization.