Sex work1 has a long and lucrative history in the United States and around the world. Today, the multi-billion-dollar commercial sex industry encompasses a  wide range of sexual services—some legal and others not—including pornography, stripping, phone and internet sex, and sexual services obtained in brothels, massage parlors, through escort services, or on the street. Until the nineteenth century, prostitution was generally legal in the United  States and flourished in large cities. In the late nineteenth century, groups concerned with social morality—especially religious groups and women’s societies  —crusaded against prostitution, leading some states to regulate and eventually ban prostitution. In 1910, Congress passed the Mann Act, which outlawed the transportation of individuals across state lines for the purpose of prostitution, and also ordered the deportation of undocumented immigrant sex workers. After various attempts to regulate prostitution, the federal government enacted the  Standard Vice Repression Act in 1919, which prohibited the buying and selling of sexual acts.