The Department of Justice is changing its long-standing policy of ignoring state laws that allow marijuana use for medicinal purposes. This federalism question played out several years ago in the Supreme Court in the Raich case; Cato’s amicus brief is available here.
Cato hosted Rob Kampia of the Marijuana Policy Project in March, and you can view the event here. Glenn Greenwald wrote an influential study for Cato on the successful decriminalization of drugs in Portugal. Greenwald notes that he gets more invitations to speak on the subject now than he did when it was published.
A good first step. Fourteen states permit medical marijuana dispensaries; I suspect more are on the way now that this hurdle has been cleared.