With 19 million regular users, marijuana is one of the most popular drugs in the country. It is also one of the most highly regulated. Until recently, such regulation was virtually synonymous with prohibition. But over the past two decades, a growing number of states have experimented with new approaches to regulating the drug, treating it more like other legal medicines or alcohol than heroin or methamphetamines. These experiments have created a new body of law governing a host of marijuana-related behaviors, from simple possessing the drug to employing those who use it, along with a host of intriguing questions regarding who has authority to regulate the drug. This course takes an in-depth look at the competing approaches to regulating marijuana, the rationales behind these approaches, and where legal authority resides for choosing among them. What are the elements of a marijuana trafficking offense? May a state legalize a drug the federal government forbids? Who is allowed to use and traffic marijuana under state law? How do states prevent diversion of marijuana into forbidden markets? Are contracts with marijuana dealers enforceable? May employers fire employees who use marijuana for medical purposes? These are just some of the questions the course will address.