This week a federal judge in California held a hearing on marijuana's legal status under the Controlled Substances Act (CSA). The context was not, as you might expect, one of those rescheduling petitions that the Drug Enforcement Administration routinely rejects. Instead it was a criminal case. U.S. v. Schweider, in which a man charged with marijuana cultivation is seeking dismissal of the indictment by arguing that the plant's Schedule I status violates the Fifth Amendment's guarantee of equal protection. The defendant, Brian Pickard, maintains that putting marijuana in the CSA's most restrictive category is so arbitrary and unscientific that it fails even the highly deferential "rational basis" test, which is the standard courts generally use for equal protection cases that do not involve a "suspect class" such as race.

While marijuana's legal status is certainly irrational as that term is usually understood, that does not mean courts will recognize it as such for constitutional purposes. To pass the rational basis test, a law must be rationally related to a legitimate government interest. But in practice, courts will accept pretty much any justification that a government lawyer can offer with a straight face. Furthermore, the courts so far have upheld the DEA's refusal to reclassify marijuana. Given the DEA's legal track record in this area, it is all the more remarkable that U.S. District Judge Kimberly Mueller, against the prosecution's objections, agreed to a hearing on whether marijuana belongs in Schedule I, which is supposedly reserved for drugs with "a high potential for abuse" that have "no currently accepted medical use" and are so dangerous that they cannot be used safely even under a doctor's supervision.

Although marijuana is supposed to meet all three of those criteria, it is doubtful whether it meets any of them. Like any psychoactive substance, marijuana has some potential for abuse, but it seems absurd to assert, as its placement in Schedule I signifies, that it has a higher potential for abuse than methamphetamine, morphine, and cocaine, all of which are Schedule II drugs, the barbiturates in Schedule III, or the benodiazepines in Schedule IV. In his motion to dismiss the charges against him, Pickard notes that marijuana has a stronger safety profile than many prescription drugs in lower schedules as well as several over-the-counter medications. To rebut the DEA's claim that marijuana has no accepted medical use, he cites the substantial body of research on marijuana's medical applications, its acceptance as a medicine by nearly half of the states, the willingness of doctors in those states to recommend it for patients, and survey data indicating that most doctors think medical use of marijuana is appropriate in some cases.

Defense witnesses elaborated on these points in their testimony this week, highlighting marijuana's long history of use, its remarkable safety, and the evidence of its medical utility. Philip Denney, a California physician specializing in cannabis recommendations, noted that the federal government implicitly recognizes marijuana as a medicine by shipping it to patients under the so-called Investigational New Drug program, which has been closed to new applicants since 1992 but still supplies several patients. The Leaf Online reports that Assistant U.S. Attorney Richard Bender objected to that testimony, but Judge Mueller allowed it because Bender was not quick enough with his objection. Bender also helped the defense by noting, while questioning Denney about a study of marijuana as a treatment for chronic pain, that "both smoked marijuana and oral THC were effective."

According to The Leaf, another assistant U.S. attorney, Gregory Broderick, "stumbled badly" while cross-examining Columbia neuropsychopharmacologist Carl Hart. Trying to highlight marijuana's potential for abuse, Broderick cited an estimate, based on data from the National Comorbidity Survey, that 9 percent of cannabis consumers qualify for a diagnosis of "substance dependence" at some point in their lives, based on the criteria laid out in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM). Hart noted that the latest edition of the DSM says tolerance and withdrawal—two indicators of what the DSM now calls "substance use disorders"—are "normal symptoms to be expected of legitimate medical cannabis use." That point "appeared to stun Broderick," The Leaf says.

Hart also might have noted that the study from which Broderick drew the estimated addiction rate for marijuana found that the rates for cocaine and heroin were substantially higher. Yet cocaine and morphine (which is what heroin becomes after injection) are both in Schedule II, which means they supposedly have a lower potential for abuse than marijuana.

The problem is that key terms in the CSA are undefined, leaving the DEA with a great deal of discretion in applying them. If you define "potential for abuse" based on a drug's appeal to recreational consumers (all of whom are, from the DEA's perspective, drug abusers), putting marijuana higher on the list than oxycodone makes sense, because it's a lot more popular. If you define "accepted medical use" as approval by the Food and Drug Administration (or completion of all the research that would be necessary for FDA approval), it follows that marijuana (as opposed to synthetic THC) is not an accepted medicine, which may also imply that it lacks "accepted safety for use…under medical supervision," especially if you consider the risk of recreational use (a.k.a. "abuse") an intolerable danger. The DEA does not have to define these terms in a way tailored to keeping marijuana in Schedule I, but so far the courts have said it can.

"It's earth-shattering to even have this hearing," Adam Levine, an adjunct professor at Stetson University College of Law in Florida, told The Christian Science Monitor. "The fact that the judge is willing to hear this case means she is willing to question if the DEA's original classification is constitutional."