Today, the DOJ released a memorandum (PDF, hereafter "Cole memo") sent to all US Attorneys' offices to "update [the DOJ's previous] guidance" on federal policy as it relates to liberalized state marijuana laws. A lot of drug reformers are hailing this memo as a great step forward for the government. I'm less convinced.
As I've written elsewhere, we've seen DOJ memos on this topic before. Indeed, the opening lines of the Cole memo directly reference the 2009 Ogden memo and its 2011 clarification. The latter, also written by Cole, effectively gutted the spirit of the Ogden memo's message to de-prioritize state-law compliant medical marijuana distributors: "The Ogden Memorandum was never intended to shield such activities from federal enforcement action and prosecution, even where those activities purport to comply with state law."
Looking at the language of today's memo, there is no concrete change in policy by the DOJ. Yes, it is encouraging that the Attorney General wants to de-emphasize regulated marijuana distribution as a prosecutorial priority, from a politically symbolic standpoint. But U.S. Attorneys don't primarily operate within the realm of politics--they prosecute people for the federal government. They have the widest discretion imaginable and literally countless federal laws with criminal and civil sanctions from which to choose to prosecute any person in their jurisdiction. Those prosecutions cost money to investigate and they have finite resources with which to work--though much larger than the resources of the would-be defendants facing federal prosecution.