People smoke marijuana, presumably, because it affects their brains, not despite that fact. Above, people in Sao Paulo, Brazil, campaign for the legalization of marijuana.
Nelson Almeida/AFP/Getty Images
Former Supreme Court Associate Justice John Paul Stevens likens making pot illegal to Prohibition. In his new book, Six Amendments, he proposes constitutional changes including a curb on an individual's right to bear arms.
Chip Somodevilla/Getty Images