When San Francisco voters elected Chesa Boudin, a public defender running on a platform to end mass incarceration, as district attorney in November, their decision was swiftly heralded as the end of an era. Boudin’s vision of criminal justice reform hit familiar points, but ones still scraping at the outer edge of the mainstream: declining to prosecute offenses like prostitution and sleeping on the street, ending cash bail, holding police accountable when they kill or use excessive force. At Boudin’s election-night party, a member of San Francisco’s board of supervisors started a chant of “Fuck the POA! Fuck the POA! Fuck the POA!” joined by the crowd, middle fingers raised.

The San Francisco Police Officers’ Association, the city’s police union, had spent more than $700,000—exceeding Boudin’s own fundraising efforts—in an effort to defeat him, pulling cash from police unions in Los Angeles, Portland, Seattle, and New York. The San Francisco Deputy Sheriffs’ Association shared a John Birch Society video calling Boudin a “communist radical” and a son of “terrorists.” Boudin’s parents were jailed for their role in an armored-car robbery, in which two police officers and a guard were killed—something even Boudin supporters thought might be used against him in the race. But San Franciscans, it turned out, voted him into office despite objections from the police and far right.

This sort of counter-campaign has become more common in the Obama and Trump eras. Police have panicked as calls for criminal justice reform have moved to the center of American politics, fueled by decades of popular movements against police brutality and prisons. Just as conservatives, going back to the Nixon era, have used debates over the lawfulness of abortion, homosexuality, and pornography to portray themselves as besieged by a liberal elite, police unions, too, now claim they are on the losing side in an ideological struggle. It may appear strange to see police alongside anti-contraception crusaders, transphobic employers, and Evangelical cake-makers on the supposed front lines of a national clash over values. But it also represents a return to the culture war’s origins.

The very idea of the culture war was born out of policing. Though the phrase didn’t come into common usage until the 1990s, provoking anxiety over law and order helped usher Nixon into the White House in 1968. Where today police unions cast Black Lives Matter activists as their persecutors, conservatives under Nixon pointed to black power activists and the anti-war left.

With James Davison Hunter’s 1991 book Culture Wars: The Struggle to Define America, the term “culture war” entered the popular lexicon. Hunter says he was inspired after reading a news story about the arrests of clergy from a range of sometimes warring faiths at an anti-choice protest. He saw the struggle emerging out of 1960s social change as a matter less of specific issues than of something much broader: “progressivism” versus “orthodoxy.”