When teachers in Chicago reached an agreement with the city to end a historic 11-day strike Thursday, it marked the closure of a labor dispute that pushed the boundaries of traditional contract negotiations – one that went far beyond fighting to increase salaries.

Setting itself apart from the dozens of other rallies, protests and strikes by teachers in more than a dozen places this year that centered on things like pay and class sizes, educators in Chicago insisted that the contract include something that has historically been outside the purview of negotiations: social safety net support for the city's most vulnerable students.

"For an outsider who is not sensitive about a lot of stuff poor folks need or the needs for public education, when you see the demand for librarians, nurses and social workers, people say, 'What they hell is wrong with this union?'" says Lee Howard Adler, a labor, criminal law and civil rights practitioner who teaches at Cornell University's School of Industrial and Labor Relations.

"But this union is about the city of Chicago, and that is a sea change in terms of traditional collective bargaining," he says. "The union is not just negotiating for a better contract, it's negotiating for the common weal, which primarily consists of low-income folks."

The new contract includes a commitment to staff all schools with a full-time nurse and a full-time social worker every day, as well as increased staff for bilingual students and students with disabilities. The highest need schools will also have access to more librarians, restorative justice coordinators and other types of support staff.

"The union is not just negotiating for a better contract, it's negotiating for the common weal."

In addition, the contract provides for full-time liaisons to help students who are homeless or living in temporary living situations and establishes "sanctuary school protections" for immigrant and refugee teachers and families

"What you see happening is teachers unions are saying to us, 'Actually if you want me to teach, breakfast and lunches for the kids is good, but they need health care, nurses, dental care and other things inside the schools because they cannot get it otherwise," Adler says. "And if we don't do that, we aren't going to really make an impact in terms of public education. Slowly but surely these unions are morphing into community-type organizations."

For Chicago, that evolution took hold in 2012, the last time the union's more than 25,000 educators walked the picket line, marking the first teacher strike in the city in more than a quarter century.

The 2012 strike was seen, at least in part, as a symbolic protest against the types of education reform policies ushered into the city by former Chicago Public Schools CEO Arne Duncan, who at the time was serving as education secretary under then-President Barack Obama, another Chicagoan, whose former chief of staff, Rahm Emanuel, was the newly elected mayor of the Windy City. Among other things the educators argued during that strike was that the city's education agenda put the interests of so-called corporate privatizers ahead of the interests of the majority of the city's students, especially its poorest and most vulnerable students.

For example, they railed against high stakes testing and the closure of poor-performing schools often replaced by charter schools run by people the communities didn't know and didn't trust. In that vein, the Chicago Teachers Union capitalized on a wave of distrust and in doing so increased its focus on many of the wraparound services that research has shown help students succeed in school.

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The union's demands this time around, Adler notes, represent new and uncomfortable territory even for Democratic mayors like Chicago's Lori Lightfoot, whose term began just four months ago.

"It pushes even a progressive, hopeful-minded, newly elected mayor, who herself comes from a minority of both color and sexual orientation, into a place that is very difficult," he says. "Mayors are not prepared to deal with this. School boards are not prepared to deal with this. This is much more than they asked for or they thought was part of collective bargaining and that creates tension and I just dont think it's going to stop."

It also speaks to why the strike lasted so long. Ultimately, union officials forced more than 80 updates to the originally proposed contract and managed to eke out additional dollars for their new agenda, even when Lightfoot insisted there was no more money to be had.

Randi Weingarten, President is the American Federation of Teachers called the strike a "paradigm shift."

"This historic fight for what students deserve – nurses and counselors in every school, librarians, class-size caps, and additional investments in special education – represents a paradigm shift: It wasn't simply a fight to mitigate the damage of austerity, it was a fight to create the conditions that both students and educators need," she said in a statement.

There's still a lot to be decided regarding the budget, Lightfoot and Chicago Public Schools CEO Janice Jackson said Thursday. The contract is slated to add as much a $500 million annually to the budget, which will be revised by November, they said.

While the teachers were on the receiving end of a lot of support, including from the 2020 Democratic presidential candidates, many others questioned whether the costs are sustainable.