When U.S. District Judge Matthew Kacsmaryk ruled Friday the Food and Drug Administration’s two-decade old approval of the leading abortion drug mifepristone violates the law, he cited the 19th century Comstock Act, a so-called anti-vice law that prohibits the mailing of contraceptives and instruments or drugs that can be used in an abortion. It has been dormant for half a century. We speak to Lauren MacIvor Thompson, a historian of birth control, about the Comstock Act and its legacy.