More than half of the states in the U.S. have legalized recreational and medical marijuana use. However, cannabis remains just as illegal as heroin on the federal level. This environment can be tricky to navigate, both for cannabis businesses and for the lawyers who advise them. In this video, Boston University law professor Jay Wexler explains how states got around the federal ban on cannabis, and Lauren Thomas, general counsel of the marijuana software company, Dutchie, describes the unique legal challenges that cannabis businesses face. (Produced by Macarena Carrizosa; Senior Producer: Andrew Satter; Executive Producer: Josh Block)