Last month’s strike by Chicago teachers and school workers was business as usual. Because business as usual for the Chicago Teachers Union (CTU) over the past decade has meant shaking the city’s political and business establishment, challenging assumptions about what a union can fight for, and setting an example for labor of a union committed to rank-and-file power and social justice.

In 2012, the CTU struck the first real blow against the corporate school reform crusade in the laboratory where it was cooked up, with a seven-day strike that forced one of the most powerful politicians in the country, Rahm Emanuel, to back down. In 2016, the teachers led a coalition of unions and community organizations in a one-day public-sector general strike to confront a Republican governor’s austerity drive to starve the schools and public services — a glimpse of the future statewide teachers’ revolts that started in West Virginia two years later.

This fall, the CTU went on offense. The two-week-long strike at the end of October ended last week with a tentative agreement that “pushed the boundaries of traditional contract negotiations . . . far beyond fighting to increase salaries,” in the words not of some pro-labor rag but the mainstream US News and World Report.