It was an amazing sight. The U.S. prosecutor responsible for sending Canada's Prince of Pot, Marc Emery, to a federal penitentiary was sitting beside Emery's wife, Jodie. Even more surprising, John McKay was there to advocate for the legalization of marijuana. McKay, the top federal prosecutor in Washington state for five years and now a law professor, believes continuing to treat marijuana users as criminals has only enriched drug-trafficking gangs and fueled violence.