If negotiations between Chicago and its teachers union fail to result in a deal, teachers will walk out and potentially shut down 500-some public schools on Oct. 17. That’s the same day that a separate union representing school aides has threatened to strike. 

Simultaneous strikes by educators and school support staff could complicate the district’s efforts to keep schools open and minimally staffed while teachers are on the picket lines. 

“This is also frankly a unified strike date,” said Chicago Teachers Union President Jesse Sharkey.

Mayor Lori Lightfoot and schools chief Janice Jackson pledged in a statement that they would keep up “aggressive” bargaining, but if teachers strike, “all CPS school buildings will remain open during their normal school hours to ensure students have a safe and welcoming place to spend the day and warm meals to eat.”

Announcing the strike date Wednesday night after a House of Delegates vote inside headquarters, Sharkey stood flanked by members of Service Employees International Union 73, which represents staff  such as bus monitors, special education assistants, and lunchroom workers.

“The reason we have set a deadline two weeks from now is because we intend to continue bargaining in good faith,” Sharkey said. “But I don’t want anyone in the city of Chicago to doubt our resolve. We mean to improve the conditions in our schools. We mean to win a fair contract.”

The delegate meeting and vote energized special education teacher Deborah Yaker. The union has demanded improved staffing, more integrity in the Individualized Education Program process, and dedicated substitutes, among other conditions for special education.  All of them are essential, said Yaker, who teaches at Hanson Park Elementary in Belmont Cragin. “It’s only to better our kids.”

Ramona T. Bonilla-Anaiel, a special education classroom aide at Lakeview High School, said she finally felt heard when members decided to strike. “We need more people, we need more staff,” said Bonilla-Anaiel, who described students missing out on their legally prescribed assistance because aides were pulled to watch other students or help with administrative tasks.

Negotiations could continue up to the strike date. In 2016, the city’s contract negotiations with the Chicago Teachers Union also were contentious, and observers saw a strike as nearly inevitable. But district officials made several concessions at the last minute, averting a walkout. 

Not even five months in office, Lightfoot is facing a potential threat of triple strikes. Besides the teachers and school support staff, Chicago Park District employees, who during the 2012 strike cared for students displaced by closed schools, also took a strike authorization vote last week. They are represented by the same union as the school support staff. 

Related: What’s a “good” pay deal for teachers? Depends on who you ask. 

Wednesday’s vote polled members of the Chicago Teachers Union’s House of Delegates, which represents various groups of teachers — some at schools and some, like clinicians and social workers, who work citywide. The union represents more than 25,000 teachers and support staff, including paraprofessionals and school social workers.  

Last week, 94% of union members voted to authorize a strike.

Setting a strike date increases pressure on Lightfoot and the city to come to an agreement with the union, or face a walkout. 

“Our members are hard workers, they serve the youth of Chicago, and they deserve a better contract,” said SEIU73 President Dian Palmer, speaking Wednesday after the strike date was announced. “Chicago can do better. I’ve seen the amounts of money that people make, but our members don’t.”

SEIU has argued that its members’ starting salary of just above $31,000 is unacceptably low.

Laying out the city’s side of the negotiations to the public earlier this week, Lightfoot and Jackson published a 420-word blog Monday explaining details of the city’s contract offer to teachers and offering an 8% pay hike for paraprofessionals. 

The city’s latest public offer to SEIU resembles the pay offer to teachers: a 16% raise across five years. As it has offered teachers, the city would absorb the rising cost of health premiums for the first three years of the deal.

Lightfoot has said that her latest offer to the city’s teachers will make them among the highest-paid educators in the country. 

The union has disregarded her offer, insisting the city lower class sizes, add support staff and put those guarantees in writing.

The teachers union contract with the district expired June 30.  

The city’s last full-fledged teacher strike was in 2012. That year, teachers walked off the job for the first time in 25 years. After seven days, they returned with gains significant enough to portray the strike as successful.