In 1919, Margaret Hennessey was taken in simply for walking down the street with her sister. A police officer decided she was suspicious, and forced both to undergo a pelvic exam. In 1918, Nina McCall was taken in, forcibly examined, and treated with arsenic under the same law. That policy, known as the American Plan, let morals squads legally take in "suspicious women" well into the 1970s.
In the name of national security, the American Plan deemed women a danger on par with the Germans. Women spread sexually transmitted diseases, the government declared, and police should arrest and isolate women to protect men from the dangers of STDs. But women didn't just face being taken in if a police officer decided they were suspicious or promiscuous. Women were forced to undergo invasive genital exams. Those found to have STDs were detained for months and treated with deadly "medicines" made from arsenic and mercury.
The American Plan might seem like a vestige of the past, but these laws remain on the books today in every state.