In a rare examination of federal marijuana law, a U.S. judge in Northern California has decided to rule on the constitutionality of a 1970 act that classifies marijuana as a dangerous drug akin to LSD and heroin.

U.S. District Judge Kimberly J. Mueller took the extraordinary step of holding a five-day hearing on the question late last year, with final arguments scheduled for next month. Her ruling, based on testimony and thousands of pages of briefs, exhibits and declarations, is expected later this year.

Lawyers say the case out of Sacramento marks the first time in decades that a judge has agreed to hold a fact-finding hearing on the classification of marijuana as a Schedule 1 drug under the 1970 Controlled Substances Act. Mueller’s decision came in response to a pretrial defense motion in a prosecution brought by the federal government against alleged marijuana growers.

One ex-pothead does not evidence for marijuana's dangers make

Attorneys for the defendants have argued that the federal marijuana law violates the Constitution's guarantee of equal protection under the law and a doctrine that gives states equal sovereignty. In addition to maintaining that marijuana is safer than many non-regulated substances, the defense contends the federal government enforces marijuana law unevenly, allowing distribution of cannabis in states where it is legal and regulated by state law and cracking down elsewhere.