One chilly winter morning, many schools across Chicago were unexpectedly closed—the teachers weren’t sick with the flu; they were sick of their working conditions. The first-ever charter-school strike in the nation, which shuttered 15 branches of Acero schools for four days and affected about 7,500 Chicago children in early December, echoed historic past strikes at traditional neighborhood schools in 2012 ad 2016. Yet their action also signaled growing militancy in the sector of schools often deemed to be “safe” from labor unrest.

Acero, one of the city’s most established charter networks, embodied the slick model of a free-market educational “solution,” publicly funded and privately run. But the Chicago Teachers’ Union (CTU) has disrupted the convention of charters as strike-free zones. Acero’s 500 striking teachers and staff were part of a cadre of unionized charter educators. Collectively, they have voted to strike at five schools since November; but all the teachers share the same goals as their district-school peers: fair teaching and learning conditions for the whole school community. Across the country this past year, teachers of all stripes—from Southern California to solid-red Kentucky—have gone on strike and rallied under the same banner, calling for fair contracts for equitable schools and respect for a politically embattled, fiscally neglected workforce.

The Acero teachers ultimately approved a contract on December 14 that addressed core economic and social tensions in city schools: calling not just for living wages, smaller classes and reasonable schedules, but also for principled school conditions, with “sanctuary” protections to shield the mostly Latinx student body from immigration authorities. All their proposals spoke to frustration with a charter model that treats schools like a commercial investment, rather than a social resource.

CTU organizer Chris Geovanis describes the system as “a corporate gravy train for investors seeking to find another way to suck up public dollars for private gain.” Yet the CTU also seeks to organize all charter teachers, accepting that they are now embedded in the public-education landscape, while also maintaining a long-term agenda of shifting the system back toward fully public community schools. Despite being opposed to the charter movement politically, Geovanis knows teachers are teachers: “We’re also talking about a very dedicated school community in terms of parents, the educators who unionized there, and particularly the paraprofessionals, many of whom hail from the very communities that they serve in.”

A key priority for Acero teachers was winning a more sustainable wage for school-support staff: Chicago teachers typically earn more than $70,000 annually, but paraprofessionals are usually paid 20 to 30 percent less—leaving many with unsustainable jobs in a city with a surging cost of living and rising rents. Meanwhile, the teaching workforce is increasingly racially homogeneous, according to the union’s research: The system has lost 16 and 21 percent of the workforce of its black and Latinx teachers since 2011 to. The pattern parallels broader trends of displacement and inequality, which has also hit marginalized black and Latinx students with chaotic school closures in their neighborhoods and deepening racial and socioeconomic segregation.

Around the same time of the Acero strike vote, teachers at four other branches of the Chicago International Charter Schools (CICS) chain also overwhelmingly approved a strike as talks plod forward with the charter operator Civitas. For them, the Acero strike was an impressive lesson in organizing. With their negotiations verging on a similar impasse, Northtown CICS math teacher and District Council member Jen Conant says, “It was inspiring to see the members at Acero fight hard for justice in their contract…and to see them get those demands met. And so I think it shows that a strike can be successful if that’s what you have to do.” Meanwhile, CICS administrators have predictably dismissed the union’s campaign, warning of supposed “obvious harm it will cause to our students and their families.”

Charters arose decades ago as a way to foster “parental choice” and “flexibility” in education, but over the years the model has been coopted by reformers looking to promote frenzied academic competition and corporate-management regimes as a way to fix failing schools. Today, however, the neoliberal canard that education can be run like a business is unraveling. In recent years, various scandals have swirled around charter management organizations, from fraud to oppressive labor practices. Overall, charter school teachers earn 20 to 30 percent less than teachers at traditional schools. Many charter schools feature highly centralized curricula driven by harsh discipline and testing regimes. Yet for all their “disruption,” charters overall do not perform markedly differently from their traditional counterparts, and education activists say that socially, charters cost communities much more than they are worth. As teacher-turned-activist Carol Burris argues, backdoor privatization through charterization “results in either a lesser education for public school students or an extra burden on the taxpayers.”

Representing teachers across the spectrum, Geovanis says CTU aims “to raise issues of equity across the city, to bring the entire sector of the workforce, in both charters and public schools, up to the same standards…and to demand the same form of accountability across the board in charters and public schools.” Resisting the charter profit structure, she argues, “brings up the standard of resources that are actually pumped directly back into classrooms, instead of into management’s pockets.”

Chicago once served as a nationwide charter laboratory, flush with philanthropic cash and pro-privatization political boosterism. Now, as labor and community backlash have led some cities to halt charter-school expansion, the sector is becoming a new frontier for teacher unions.

“What we’ve seen in Chicago is that there’s a difference between charter operators and charter educators,” says Jen Conant, a math teacher and CTU District Council at CICS. “The educators in charter schools want what’s best for their students, just like any teacher at a traditional public school. And that by unionizing and giving teachers that voice and the power to work to change their school, that actually improves the education system overall.”

When all school workers defend their livelihoods and the communities they serve, the movement, not the just the campus, becomes the foundation for educational democracy, and privatization becomes not the answer but the antithesis of real opportunity. A genuine chance to succeed at any school should be a right, not a commodity.