It started with a coalition of disgruntled Americans, then a handful of governors took up the cause last year, and now -- for the first time in nearly 20 years -- a federal court will hear oral arguments in a lawsuit challenging the classification of cannabis as a dangerous drug without medical benefits.

In the case, Americans for Safe Access v. Drug Enforcement Administration, the court will be presented with scientific evidence regarding the medicinal effects of marijuana, and is expected to rule on whether or not the Drug Enforcement Administration acted appropriately in denying a petition to reclassify cannabis, filed by a collection of public interest organizations back in 2002.

"Medical marijuana patients are finally getting their day in court," Joe Elford, chief counsel with ASA, said in a recent statement. "This is a rare opportunity for patients to confront politically motivated decision-making with scientific evidence of marijuana's medical efficacy."

Under federal law, a schedule I prohibited substance is defined as having “a high potential for abuse” and “no currently accepted medical use in treatment.” Heroine and LSD are classified alongside marijuana as schedule I, while cocaine, opium and methamphetamine are classified as schedule II, meaning they have "some accepted medical use."

Other groups, including the American Medical Association, the American Nurses Association and the American Academy of Family Physicians, support medical access to the drug or its reclassification, while the California Medical Association has called for full legalization.

Donald Abrams, chief of hematology-oncology at San Francisco General Hospital, recently described the effectiveness of medical marijuana in the treatment regimens of cancer and HIV/AIDS patients. "I see patients who have loss of appetite, nausea and vomiting from their chemotherapy, pain on and off of opiates, anxiety, depression, and insomnia," he said in a press briefing last week, adding that these are just some of the conditions that can be alleviated by the use of medical marijuana.

In its rejection of the ASA’s rescheduling petition in 2011, the DEA cited a 4-year-old Department of Health and Human Services paper that found no consensus on medical uses for marijuana, but it did not take into account studies showing the medical benefits of marijuana on the grounds the studies did not meet the standard of double-blind FDA approval trials.

"[T]here are no adequate and well-controlled studies proving (marijuana's) efficacy; the drug is not accepted by qualified experts..." wrote DEA administrator Michele Leonhart in a July 8, 2011 letter. "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."

A similar petition calling for marijuana to be reclassified as a schedule II drug was filed with the DEA in 1972, and in 1988, following a federal hearing, Administrative Law Judge Francis Young ruled that marijuana should indeed be reclassified. But that verdict was rejected by then-DEA administrator John Lawn and in 1994, his rejection was upheld by the D.C. Court of Appeals.

The current case will be heard by the U.S. Court of Appeals for the D.C. Circuit on Oct. 16.

Related on HuffPost:

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  • Alaska

    Legalized for medical use. <a href="http://www.flickr.com/photos/alanasise/6847095796/" target="_hplink">Flickr: alana sise</a>

  • Arizona

    Legalized for medical use. <a href="http://www.flickr.com/photos/billward/110338154/" target="_hplink">Flickr: Bill Ward's Brickpile</a>

  • California

    Legalized for medical use. <a href="http://www.flickr.com/photos/gerbache/2260207829/" target="_hplink">Flickr: gerbache</a>

  • Colorado

    Also legalized possession by non-medical users. <a href="http://www.flickr.com/photos/dok1/520845832/" target="_hplink">Flickr: dok1</a>

  • Connecticut

    Legalized for medical use.

  • District Of Columbia

    Legalized for medical use. <a href="http://www.flickr.com/photos/bigberto/2770838680/" target="_hplink">Flickr: ~MVI~ (off to coron)</a>

  • Delaware

    Legalized for medical use. Flickr: <a href="http://www.flickr.com/photos/dougtone/7749689644/">Doug Kerr</a>

  • Hawaii

    Legalized for medical use. <a href="http://www.flickr.com/photos/ricardo_mangual/6006230817/" target="_hplink">Flickr: Ricymar Fine Art Photography</a>

  • Illinois

    Legalized for medical use.

  • Maine

    Legalized for medical use. <a href="www.flickr.com/photos/indywriter/2683524563/" target="_hplink">Flickr: indywriter</a>

  • Maryland

    Legalized for medical use.

  • Massachusetts

    Passed ballot initiative for legalized medical marijuana in 2012.

  • Michigan

    Legalized for medical use. <a href="http://www.flickr.com/photos/kayoticblue/213316452/" target="_hplink">Flickr: ckay</a>

  • Montana

    Legalized for medical use. <a href="http://www.flickr.com/photos/csbarnhill/2633187564/" target="_hplink">Flickr: csbarnhill</a>

  • Nevada

    Legalized for medical use. <a href="http://www.flickr.com/photos/http2007/4699361533/" target="_hplink">Flickr: http2007</a>

  • New Hampshire

    Legalized for medical use.

  • New Jersey

    Legalized for medical use. <a href="http://www.flickr.com/photos/paulflannery/4021996652/" target="_hplink">Flickr: psflannery</a>

  • New Mexico

    Legalized for medical use. <a href="http://www.flickr.com/photos/everyskyline/3134662783/" target="_hplink">Flickr: michaelwhitney</a>

  • Oregon

    Legalized for medical use. <a href="http://www.flickr.com/photos/d-powell/2099638403/" target="_hplink">Flickr: digging90650</a>

  • Rhode Island

    Legalized for medical use. Also decriminalized possession of less than one ounce.

  • Vermont

    Legalized for medical use. <a href="http://www.flickr.com/photos/bryanalexander/6129117/" target="_hplink">Flickr: BryanAlexander</a>

  • Washington

    Legalized for medical use. Also legalized possession by non-medical users. <a href="http://www.flickr.com/photos/rose_braverman/6924724331/sizes/l/in/photostream/" target="_hplink">Flickr: Rose Braverman</a>