Last week, a federal judge indicated she was considering nine defendants’ arguments that Congress’ decision to treat marijuana as a Schedule One controlled substance is unconstitutional.

For five days, attorneys for the accused marijuana growers presented an array of evidence to support their argument that scientific literature simply does not support the current categorization of cannabis.

The defendants face a steep burden. Rational basis review, the level of scrutiny applied to Congress’ classification of marijuana, examines whether Congress could rationally have believed that its decision to ban the production and distribution of marijuana would advance its legitimate interest: the promotion of public health and welfare. Similar challenges have failed in the past. This latest challenge attempts to distinguish itself from those failed attempts by focusing the attack on Congress’ recent decision to prohibit Justice Department officials from interfering with states that authorize the use, distribution, possession or cultivation of medical marijuana.

In its reply brief, the defense challenged the federal government to explain “how Congress’ present actions are at all rational, for, by insisting marijuana be classified as the most dangerous drug, but cutting off all funds for enforcing the law in states where this most dangerous drug is being distributed.” Congress, they argued, has abandoned “any ostensible rational belief that the need to promote public health and welfare mandates the outright ban on the production and distribution of this substance under Schedule I.”

This latest challenge to the federal classification of marijuana is the most recent in a series of nationwide marijuana legalization efforts and the defendants’ briefs appear to take advantage of Congress’ recent decision to not fund certain marijuana enforcement efforts. The judge’s ruling is expected sometime in the next three weeks.