Medical marijuana dispensaries scored a major win on Monday when a federal judge ruled that the Department of Justice cannot prosecute legal providers of medical cannabis. 

In his ruling, Senior District Judge Charles R. Breyer lifted an injunction against a California dispensary, the Marin Alliance for Medical Marijuana, and its founder, Lynette Shaw, ruling that a budget amendment Congress approved last year requires the federal government to respect state marijuana laws. The DOJ is thus precluded from criminally prosecuting organizations like MAMM that comply with state regulations.

The amendment, sponsored by Reps. Dana Rohrabacher (R-Calif.) and Sam Farr (D-Calif.), was added to last year's federal spending bill. Under the provision, the Justice Department is prohibited from using federal funds to undermine state medical marijuana programs. The Rohrabacher-Farr amendment came in response to a renewed federal crackdown on the medical marijuana industry in California, where medical pot has been legal since 1996. MAMM, located in Fairfax, California,...