"Concentration camps for prostitutes."

That was the phrase Scott Stern heard a history professor utter in 2011, when Stern was a freshman at Yale University. The professor was lecturing about how difficult it was to treat sexually transmitted infections in the era of World War I, and the lengths to which the government went to prevent their spread.

Intrigued, Stern looked online for more information, but found nothing. Searching elsewhere, he gradually uncovered a trove of material about what was called the American Plan. The forgotten initiative had resulted over several decades in the detainment of perhaps 100,000 women or more around the country, all on the mere suspicion of carrying STIs.

Many of the women were imprisoned – usually without due process – and forced to undergo painful treatments, typically injections of mercury or arsenic. But these toxins were only marginally effective at curing STIs -- assuming the women even had them (and many surely didn’t, Stern said, because of the high rate of false positives back then). The mass quarantines were compounded by the shame and stigmatization the women felt long after release.

The American Plan became an academic focus of Stern’s as he worked his way toward a master’s degree; after graduating, the Pittsburgh native returned to his boyhood home, in Squirrel Hill, and spent two-and-a-half years researching and writing what became his first book.

The Trials of Nina McCall: Sex, Surveillance, and the Decades-Long Government Plan to Imprison “Promiscuous” Women (Beacon Press) tells the story of the American Plan partly by following McCall, a Michigan woman who at 18 was detained, diagnosed as “slightly infected with gonorrhea,” and did three months of hard labor at Bay City Detention Hospital.

“Using Nina as the protagonist allows us not only to see this and see how the American Plan worked up close, but also hear the voice of one woman who was locked up on the American Plan and really kind of get to know her,” he said.

This is the stuff of The Scarlet Letter and The Handmaid’s Tale, but historically documented, and within living memory. But Stern knows McCall’s story in detail only because, like many of the women so detained, she fought back, suing the government over her treatment. The book is packed with historical context about the American Plan, from its roots in Victorian-era misogyny, and pseudo-scientific war-time public-health concerns, to the alliance between private crusaders and government officials that allowed the Plan to be enshrined in legislation in every state in the union.

The laws were written with gender-neutral language, but almost invariably targeted women, Stern noted.

“The American plan is about an attitude toward women and an attitude toward promiscuity or rather sexual behavior,” said Stern, “and this Victorian notion that the sexual lives of young women need to be policed and that young women who stray from conventional ideas of morality need to be policed.”

The American Plan was sanctioned by many powerful Americans, from figures you’d expect, like Elliot Ness, and others whom you might not, including John D. Rockefeller and Eleanor Roosevelt.

Some of the women detained were sex workers; many, like McCall, were not. And while STDs were indeed rampant in early 20th Century America, Stern emphasizes that public health was scarcely affected by the American Plan.

“This was this was not actually about controlling syphilis and gonorrhea,” he added, “This was about controlling women at a time when women were starting to get a formal education for the first time, right around the time when the suffrage movement was reaching its peak.”

Women got the right to vote in 1920, a couple years after American Plan laws began to go on the books in earnest.

“There is … no valid public health reason to lock up just one gender,” Stern said. “It takes two to tango.”

But it didn’t take much for a woman to get detained. Walking alone might raise sufficient suspicion of promiscuity – or walking with a man who wasn’t your husband. Drinking in a bar or dressing a certain way could also get you trouble. Enforcement of the laws also disproportionately targeted working-class women and women of color, he said.

Perhaps shockingly, all the American Plan laws remain on the books, says Stern. They were enforced in many states into the 1950s, and in some places trotted out during the HIV/AIDS epidemic of the 1980s and ’90s.

Stern said that because these laws were passed and enforced mostly by local authorities, getting a precise count of the women detained is nearly impossible. The number is “tens of thousands” at a minimum, but more likely “well over 100,000 women,” he said.

That decentralization has also contributed to the American Plan’s near-disappearance from history. So, too, however, did the stigma affixed to women who were detained under the plan, who were unlikely to tell their stories.

Still, Stern has documented that many women did resist – physically assaulting their jailers, for instance, escaping detention, and, like McCall, suing the government.

Stern documents that McCall’s resistance began when she, as a teenager, stood up to the doctor who – after what was her first gynecological exam – told her she was “slightly infected with gonorrhea.” When McCall protested that she had never had sex, the doctor said, “Young lady, do you mean to call me a liar?” And Stern said that McCall said, “Yes, yes, sorry, I do.”

“It’s hard to overstate just how bold an 18-year-old woman in 1918 would have had to have been to call a male authority figure a liar to his face,” Stern says.

Stern is now studying at Yale Law School, and living in New Haven, Conn. The film rights to The Trials of Nina McCall have been bought by Cathy Schulman, the Hollywood producer behind Crash and Edge of Seventeen.

Scott Sterm reads from The Trials of Nina McCall at 6 p.m. Tue., May 15, at the Carnegie Library main branch, in Oakland, courtesy of Pittsburgh Arts & Lectures. Admission is free; register at pittsburghlectures.org.