Vermont Senator Bernie Sanders (A.B. ‘64) joined Chicago-area educators and school employees last Tuesday for a rally as the Chicago Teachers’ Union (CTU) and Service Employees International Union Local 73 (SEIU) began a strike authorization vote.

“I am so proud to be with you here tonight,” Sanders told the union members assembled at the CTU headquarters, “to say to the city of Chicago: sit down with the CTU. Sit down with SEIU. And negotiate a good-faith contract that is just, that is fair, that treats the teachers and the staff in this city with the respect and dignity they deserve.”

Following the rally, union members had until Thursday to vote on a potential strike. CTU announced that the strike authorization passed with 94% of votes in favor. The strike could begin as soon as October 7th.

CTU represents more than 25,000 public school educators in Chicago and is a chapter of the American Federation of Teachers (AFT). SEIU represents more than 29,000 public employees in Illinois and Indiana, including support staff at Chicago-area schools. Two unions at UChicago are affiliated with AFT and SEIU: Faculty Forward—the union representing non-tenure track faculty—is affiliated with SEIU, and Graduate Students United—which represents graduate workers—is affiliated with AFT.

Chicago teachers have been engaged in contract negotiations with the city and Chicago Public Schools (CPS) for more than 9 months. The previous union contract expired in June, and Mayor Lori Lightfoot (J.D. ‘89) had hoped to lock in a new contract before CPS students returned to school earlier this month.

As mandated by the Illinois Educational Labor Relations Act, Steven Bierig, an independent fact-finder, was called upon to make recommendations for a contract between CTU and CPS. After a two-day hearing in July, Bierig submitted his findings to union and school board leaders in August.

The City initially offered a 14% raise and 1.5% in increased employee health contributions over a five year contract. Based on Bierig’s recommendation the City increased its offer to a 16% raise and a 1% increase in employee health contributions over the same time frame. “That’s real dough,” Lightfoot said.

CTU had proposed a 15% pay raise over three years as an effort to keep up with a rising cost of living in Chicago. The union had also asked that several other issues be negotiated in the contract, including shrinking class sizes, increased affordable housing for teachers, a ban on school closings, and mandating a minimum staffing commitment for social workers, nurses, and other school support staff. Bierig ruled these concerns outside of his jurisdiction and CTU argues the City has made insufficient commitments to solving them.

More than a dozen speakers preceded Sanders at the rally, including several aldermen and much of the leadership of the Chicago labor movement.

Several speakers invoked a recent strike at the University of Chicago Medical Center (UCMC) by National Nurses United (NNU) to argue that withholding labor can be a powerful tool for unions in contract negotiations.

Nurses represented by NNU “went out on a historic strike—the first one ever—at UChicago Medicine just a few days ago,” said 35th ward alderman Carlos Ramirez Rosa.

“The nurses are on strike at the University of Chicago Medical Center,” said Dan Montgomery, president of the Illinois Federation of Teachers. “That’s a strike for life and death. They’re striking for the lives of their patients.”

“Everyone is going on strike in this city,” observed 20th ward alderman Jeanette Taylor, who represents most of Woodlawn on the City Council. “I am in this seat because of you, and I’m humble and I thank you. Every time I walk in City Hall I take you with me.”

“We’ve gotta get it in writing,” Taylor said of a potential CTU contract. “We’ve been bamboozled too many times to be silent.”

CTU president Jesse Sharkey said he would prefer that contract negotiations not force the union to strike, but said many of CTU demands were not addressed in the City’s proposals. “If you cut me I bleed CTU red, and if it takes a strike, so be it,” Sharkey said.

Sanders spoke last, around 8pm, and received several standing ovations from the crowd. His speech touched on many of the proposals core to his presidential run, including abolishing student debt and making public colleges and universities tuition free.

“Four years ago when I came to Chicago to campaign here, I said we must make public colleges and universities tuition free,” Sanders said. “In the last four years, 12 states in this country have moved in that direction. When we are in the White House together, we’re gonna make public colleges tuition free in every state.”

Sanders also highlighted his proposals to increase government revenue by taxing the richest Americans, including a wealth tax he unveiled the day prior to the rally.

“My critics—of which, needless to say, there are more than a few—say ‘Bernie, how are you gonna pay for it?’ I’ll tell you exactly how we’re gonna pay for it. We’re gonna pay for it through a tax on Wall Street speculation.”

Several other presidential candidates offered their support to Chicago teachers from afar. Massachusetts Senator Elizabeth Warren, who many see as Sanders’ rival for the left-most votes in the Democratic Primary, tweeted her support for CTU before the strike authorization vote, followed by a video on Friday emphasizing her experience as a public school teacher. Vice President Joe Biden also tweeted in support of CTU on Monday. California Senator Kamala Harris and Former Secretary of Housing and Urban Development Julián Castro each tweeted their support as well.

“Brothers and sisters, I want to thank you so much,” Sanders said. “You are doing some of the most important work that can possibly be done in our country. You are giving hope to the children. You’re giving love to the kids. You’re educating the kids and preparing the kids in a very difficult time to go out in the world and succeed.”