Several factors may be at play. Federal marijuana cases have dropped almost 50 percent since 2013—the same year that former U.S. Deputy Attorney General James Cole issued a memorandum, colloquially known as the “Cole memo,” to federal prosecutors on marijuana enforcement priorities. The document has generally been interpreted as a message to U.S. attorneys not to prosecute people complying with state cannabis laws.
Attorney General Jeff Sessions rescinded that memo in January, but he later said it wouldn’t necessarily lead to an increase in federal marijuana cases. The Justice Department doesn’t have the resources to take on “routine cases,” he said.
Paul Armentano, deputy director of NORML, told Marijuana Moment that he viewed the trend as a reflection of “shifting federal priorities among both U.S. drug enforcement and border agents” and “may also be attributable to the reality that international drug trafficking organizations in recent years, following the advent of legalization in several U.S. jurisdictions have largely shifted their efforts away from marijuana.”
In other words, more of the market for cannabis is now being supplied by people following new state laws, so there are fewer people for the feds to prosecute in marijuana trafficking cases.