Over the decades, the government expanded the Marihuana Tax Act and passed other prohibition-minded legislation, but it was counterculture icon Timothy Leary who ultimately brought the tax down. The police arrested and convicted the former Harvard professor for cannabis possession without a tax stamp. Dr. Leary fought the charges all the way up to the U.S. Supreme Court. In 1969, the Justices heard arguments in Leary v. United States and unanimously sided in favor of Dr. Leary. The ruling, in effect, declared the Marihuana Tax Act unconstitutional, leading to its repeal, but Congress kept prohibition rolling by passing the Controlled Substances Act in 1970.