sentences:  Cannabis was then effectively outlawed at the federal level, following the passage of the Marihuana Tax Act of 1937.Cannabis remained mostly an underground drug until the 1960s, when it found widespread popularity among large numbers of young people and hippies, and was used commonly at protests against the Vietnam War.Cannabis was officially banned for any use with the passage of the 1970 Controlled Substances Act, subsequent to the Supreme Court's overturning of the Marihuana Tax Act in 1969 (in the case "Leary v. United States").