There seems to be no more controversial place in American life right now than the public restroom. It’s become the latest battlefield in the culture wars — an issue so electric that the most powerful politicians in the country have weighed in: President Barack Obama, Attorney General Loretta Lynch, Hillary Clinton, Bernie Sanders, Ted Cruz, and Donald Trump.

In 2016, at least 15 states have considered “bathroom bills” similar to the legislation recently enacted in North Carolina, which blocks transgender people from using bathrooms that don’t correspond to the sex listed on their birth certificates. Opponents of these proposals have argued that the real impetus isn’t restroom protocol; it’s part of an ugly attempt by social conservatives to score a victory against a surging LGBT movement.

But it would be a mistake to see the bathroom bills as nothing more than a desperate last-minute counterpunch against an ascendant gay-rights movement. There’s a forgotten history at play: For as long as public restrooms have existed, they’ve been a political flash point.

For generations, Americans have imparted bathrooms with their deepest anxieties about changing social norms and practices. From the Industrial Revolution to Jim Crow to women’s lib to today, restrooms have been a proxy for political fights on almost every major issue in American life — race, class, gender, crime, sexuality, you name it. Much like our current foray, past bathroom brawls drew the involvement of the marquee figures of those eras — President Jimmy Carter, Governor Ronald Reagan, President Lyndon Johnson, and Rev. Martin Luther King Jr., and Phyllis Schlafly, among many others.

If the past is any guide, we shouldn’t count on the current struggle over restrooms for transgender people being easy or quick. In fact, bathrooms have proven a surprisingly powerful political lever over the years. They’ve been pivotal in many political arguments — and, in perhaps the most masterful harnessing of bathroom anxiety in American history, a largely invented controversy over unisex bathrooms in the 1970s ultimately killed off the almost-enacted Equal Rights Amendment to the Constitution.

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For more than 100 years, Americans have projected their most profound fears about social change onto public restrooms. And just as we’ve seen in the 2016 campaign — with Ted Cruz running an ad that asks “Should a grown man pretending to be a woman be allowed to use … the same restroom used by your daughter? Your wife?” — women’s restrooms especially have borne the brunt of these fears.

As public restrooms emerged in the 19^th century, American men and women both viewed ladies’ rooms as a public extension of the home — a safe spot where women could escape the outside world and its dangers. As the number of women working in factories and mills increased, so too did cultural anxieties about ladies leaving the protection and privacy of the domestic sphere. Governments started making bathrooms their business, enacting laws requiring sex-segregated public restrooms, beginning with Massachusetts in 1887. By 1920, 43 other states had put similar laws on the books.

In the decades that followed, changes in the 20^th-century middle-class American home similarly shaped attitudes and laws regarding public restrooms. Following World War II, suburbia blossomed and white middle-class American families moved into new homes that exhibited luxuries previously available to only the upper class — including multiple restrooms. Now, middle-class parents could enjoy master bathrooms, with separate, more modest accommodations for their children. In some homes, parents even assigned their sons and daughters different bathrooms to avoid any improper moments between their children. These changes strengthened the idea that the bathroom should be a zone of personal privacy, but also endowed bathrooms — even in anodyne suburban homes — with a latent sexual charge.

Such attitudes helped shape white resistance to desegregation of public spaces, restrooms included, during the civil rights movement. In the Jim Crow South, white racism branded black men as sexual predators imperiling the virtue of white women. With black women seen as their accomplices, integrated restrooms posed a threat: unclean and oversexualized black men would, by proxy, have access to white women.

In 1961’s Turner v. Randolph case, the City of Memphis, Tennessee, employed this exact rationale in opposing the desegregation of restrooms in its public library. “The public welfare” was at stake, the City argued, because venereal diseases were commonplace among blacks, and an integrated ladies’ room would put white women at risk of catching VD from black women. During this era, segregationist literature across the South told parents to keep their daughters home from integrated schools lest they catch VD from young black women now using the school restrooms. In Mississippi, one white second-grade teacher worried that if her school integrated, her white students would “contract syphilis” from toilet seats used by black children.

At the same time, public fears about a “homosexual menace” overtaking the nation stoked alarm that young boys faced sexual danger in public restrooms. A police crackdown on same-sex sexual activity in men’s restrooms in the 1950s and 1960s — this at the time when many Americans equated homosexuality with pedophilia — deepened these worries.

Public officials distributed pamphlets warning about “child attackers” who hid out in public restrooms to capture their prey. “Never wait or play around toilets. Always leave immediately,” a popular 1954 pamphlet used across the nation instructed. The 1961 public service film, “Boys Beware,” broadcasted those ideas to an even larger audience. “Public restrooms can often be a hangout for the homosexual,” a narrator ominously explained. “Bobby and his friends hadn’t noticed the man who had been in the restroom when they changed.” Bobby and his friends had erred in treating their restroom as a safe space — the very mistake predators relied on to carry out their crimes. School children understood the message: Boys had to be on guard when they entered public restrooms, vigilant against the violent, sexual dangers that lurked there.

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While the homophobic “lavender scare” had subsided by the 1970s, conservative activist Phyllis Schlafly drew on both its legacy and on the white backlash to the civil rights movement to mount a brilliant attack on the Equal Rights Amendment. A proposed constitutional amendment guaranteeing sex equality under the law, the ERA had been passed by Congress in 1972 and sent to the states for ratification. By 1974, 33 states had passed the ERA, just five short of the number needed for full ratification. Though the odds of stopping the amendment looked poor, Schlafly quickly organized a national movement to block the ERA’s adoption.

Schlafly’s main objection to the amendment concerned its second clause, which she worried would give the federal government unrestricted power. She quickly realized that this technocratic argument inspired little passion among her foot soldiers. Instead, they wanted her to focus on how the amendment would change their lives and their families. Schlafly contended that if passed, the ERA would destroy the traditional family — and thus society itself — by eradicating sexual difference.

The argument depended on fanciful leaps of logic, but after the tumult of the civil rights movement and the sexual revolution, her audience was primed to imagine the worst. In Schlafly’s telling, the consequences of an ERA would know no end. While feminists argued that the ERA would provide women with equal protections in areas like employment and education, Schlafly warned the amendment’s effects would extend into that rare sanctuary of privacy and safety that women had outside the home: the ladies’ room.

Once gender equality had been guaranteed under the Constitution, Schlafly cautioned, no laws could prevent men from entering women’s bathrooms. Public restrooms could become a dangerous trap.

ERA advocates called her bathroom talk ridiculous. “There's been a lot of distortions about the Equal Rights Amendment,” said President Jimmy Carter. “It doesn't say anything about bathrooms.” But Schlafly’s attack was shrewd, pulling together the different strands of bathroom panics that had excited Americans for decades. Slyly drawing on the loaded language of the prior decade, Schlafly and her allies warned that ERA would “integrate public toilets.” Since most Southern states had yet to vote on the ERA, language that suggested it would follow the recent racial integration of public restrooms with sex integration ensured a spirited Southern opposition to the amendment.

Tapping into the oldest concerns about women’s public restrooms, a pamphlet from Schlafly’s powerful STOP ERA organization claimed that women would lose their “right to privacy based on sex” in “public restrooms and other public facilities.” The ERA, said former Governor Ronald Reagan, could “degrade and defeminize women by forcing them to mingle with men in close, intimate quarters.” As it always had, the notion of privacy carried deeper meanings of safety and protection, which Schlafly now warned would be eliminated. The ERA, its opponents charged, would grant men, including rapists and pedophiles, equal access to women’s restrooms.

In describing rapists and pedophiles hiding out in public restrooms ready to attack unsuspecting women and girls, Schlafly summoned the fear of homosexual predators stalking boys’ restrooms, and refashioned it for a new crisis. Convinced that perverts had long made use of men’s restrooms, ERA’s opponents easily suggested that a new crop of deviants would exploit the law. Anti-ERA cartoons showed rapists freely entering restrooms where a “Persons” sign had replaced the one for “Ladies.” Conservative women besieged their state legislators with letters demanding they vote against the “Common Toilet Law,” the new name they had given the ERA. Some protesters donned costumes, dressing as outhouses adorned with “Theirs” signs, — an effigy of the unisex restrooms they believed the ERA would require.

Lawmakers responded, many explaining they were voting against the ERA to ensure their wives and daughters would never face a sexual predator in their public restrooms, ensuring the amendment’s defeat. “I’ve had enough civil rights to choke a hungry goat,” bellowed Clay Smothers, a Texas state legislator speaking at an anti-ERA rally in 1977. “I ask for victory over the perverts of this country. I want the right to segregate my family from these misfits and perverts.”

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Today, that same logic is behind North Carolina’s bathroom bill and similar measures being pushed throughout the country. Drawing from Schlafly’s playbook, conservative activists have reframed these civil rights matters as public safety concerns.

In advance of Houston’s rejection of an anti-discrimination ordinance in November 2015, one political ad blanketing TV airwaves repeated the image Schlafly had developed 40 years before, showing a sketchy man trapping a young girl in a bathroom stall. “It was about protecting our grandmoms and our mothers and our wives and our sisters and our daughters,” Texas’ Lt. Gov. Dan Patrick said after the Houston referendum passed.

North Carolina Governor Pat McCrory has echoed that sentiment. This February, he warned members of the Charlotte City Council that passing a nondiscrimination ordinance guaranteeing legal protections for LGBT people could “create major public safety issues by putting citizens in possible danger from deviant actions by individuals taking improper advantage of a bad policy.” A few weeks later, McCrory signed HB-2, the “bathroom bill.”

For decades, politicians and activists have met cultural unease over restrooms with campaigns and laws aimed at regulating and protecting those spaces. Just as frequently, those acts have depended on curtailing civil rights. The cruelest irony of it all may be that the language of protection and safety — tossed about so freely in these debates — is often used to ensure the very loss of those things for the people who need it most.