Attorneys in California last week delivered their final arguments in a court hearing that could pose an unprecedented challenge to the official classification of marijuana as a Schedule I controlled substance in the United States — one that would complicate federal justifications for prohibition amid a wave of cannabis liberalization efforts across the country.

The hearing is part of US v. Schweder et al., in which nine defendants face criminal charges in the Eastern District of California for growing marijuana in the state's Shasta-Trinity National Forest. Last year, defense attorneys Zenia Gilg and Heather Burke argued that their clients are innocent of any crime because there is no rational basis for the Drug Enforcement Administration to apply the Schedule I standard that a drug must have "no currently accepted medical use in treatment in the United States" to cannabis. After all, medical marijuana is now legal under state law in 23 states and DC.

In response, US District Judge Kimberly Mueller did something no federal judge had done in decades: agree to hold a hearing on the constitutionality of marijuana's Schedule I classification. Initial testimony took place last October in Sacramento. After closing arguments from both sides on Wednesday, Mueller said she expected to issue a ruling within 30 days.

If she finds for the defense, the criminal case will be dismissed, with the prosecution almost certain to file an appeal.

The rarity of Mueller's move has provoked breathless speculation about the potential for this case to undo federal marijuana prohibition. "The future of national marijuana laws could be up to one person," intoned CBS13 TV in Sacramento.

In 2012, researchers at the University of California Center for Medicinal Cannabis Research summarized their clinical trials on marijuana's benefits in the Open Neurology Journal, suggesting that its reclassification was a matter of time.

"Evidence is accumulating that cannabinoids may be useful medicine for certain indications," they wrote. "The classification of marijuana as a Schedule I drug as well as the continuing controversy as to whether or not cannabis is of medical value are obstacles to medical progress in this area. Based on evidence currently available the Schedule I classification is not tenable; it is not accurate that cannabis has no medical value, or that information on safety is lacking."

With the increasing use of other Schedule I substances like psilocybin and MDMA in clinical trials to test their therapeutic promise, the reclassification of marijuana on medical grounds might possibly open the door for those drugs, too. It's a dramatic narrative, with echoes of other landmark courtroom advances in civil rights from desegregation to gay marriage. But experts say that the legal tangle around marijuana can't really be undone by one judge's gavel.

"It's an uphill battle the defendants have, just because of the level of deference courts show to legislative decisions," Alex Kreit, associate professor at the Thomas Jefferson School of Law in San Diego, told VICE News. "It's not the court sitting there saying, well, in its opinion there's sufficient evidence to show whether marijuana has medical value. It's the judge saying, is this a case where the DEA's decision is so out of the realm of what the evidence shows that there's no rational basis for it? It's just a really demanding standard."

Mark Kleiman, a professor of public policy at the University of California-Los Angeles who has written widely on drug policy, agrees that a ruling for the defense is a long shot.

"It's an interesting argument, but it's contrary to case law," he told VICE News, noting that the apparent change in public attitudes about marijuana over recent decades is "irrelevant" to established precedent.

Even if Mueller does find for the defense, and the decision holds up under appeal, it wouldn't mean marijuana would instantly become fully legal for medical or any other use. The judge can only strike down marijuana's current classification, not establish a new one.

That could only be done by the DEA through the process established under the Controlled Substances Act, or by Congress making a new law. And even if the federal government were to acknowledge the medicinal application of cannabis, anyone wishing to prescribe, market, or sell marijuana in that capacity would have to be approved by the Food and Drug Administration — another tall order.

"In order for DEA to [reclassify marijuana as a medicine], we have to receive a recommendation from the FDA," Special Agent Matt Barden, a DEA spokesperson, explained to VICE News. "Somebody has to show that it is medicine. It has not been proven to the FDA yet. Once it's proven to be medicine, then it goes through the process of figuring out which classification it needs to be in."

The broad specification of the current scheduling — as "marijuana (cannabis)," rather than particular chemical compounds or strains — make a blanket rescheduling under the Controlled Substances Act unlikely.

"Cannabinoids are [medically] valuable," said Kleiman. "That does not make marijuana a medicine. 'Blow some weed' is not a prescription. Marijuana is always going to be Schedule I because it's not the name of a medicine. It's the name of a plant. Some marijuana has 22 percent THC" — the plant's primary psychoactive compound — "some has 3 percent. There's no reason to think the same strain is as useful for treating MS as it is for anorexia."

Cannabis extracts and synthetic cannabis products, such as the already approved Marinol, would probably have an easier time meeting FDA standards for pharmaceuticals, Kleiman said. A promising strain known as Charlotte's Web yields a high cannabidiol extract that has won attention for its ability to treat epilepsy in young children.

Legalization advocates will continue to hope that a judicial magical bullet can resolve the conflict between federal and state law in an instant, avoiding slow, expensive legislative campaigns. But if those hopes seem dim, a pro-defense ruling in Schweder could at least move that political process along.

"If this judge holds for the defendants, that might be something that hastens Congress realizing that we need to do something about this," Kreit said. "I imagine Congress would love for it to be the case that a judge could just resolve this. But at some point, it's going to become clear to Congress that they need to do something here."