For thousands of years, the cannabis plant was a crucial crop in helping civilizations evolve, used for products from clothing to medicine. But then in the early 20th century, the American government demonized it. Is weed a wonder drug or dangerous habit? In this piece, Larry Potash explores the backstory of cannabis’ comeback. See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.