"The mayor today has dashed our hopes for a quick settlement," said CTU President Jesse Sharkey.
In the letter, Mayor Lori Lightfoot called on teachers to return to work while negotiations continue, citing progress made at the table.
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"The students and families of Chicago cannot afford to be out of school for any longer, which is why we are asking you to end the strike and encourage your members to return to work while bargaining continues," Lightfoot wrote.
"Enough is enough. There is no further excuse to keep our kids out of school," she said at a media availability Monday. "Beyond what we put on the table, there is simply no more money."
"To have that letter say basically go back to work, and I don't have any more money...huh?" said CTU Vice President Stacy Davis Gates.
The mayor said Chicago Public Schools has already agreed to a nurse and social worker in every school, and put in writing concessions on class size and staffing. But CTU said there's no way to enforce those promises and called the mayor's letter a setback to the progress they'd been making.
"The mayor has said she was willing to put in writing a series of promises, but apparently her pen ran out of ink halfway through her homework assignment," Sharkey said.
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CPS announced Monday afternoon that classes have been canceled for Tuesday, the sixth full day and fourth school day of the strike. Presidential Candidate Elizabeth Warren will travel to Chicago Tuesday morning to rally with striking teachers, her campaign said, giving the union a high-profile backer.
The union said progress was made over the weekend but viewed the mayor's letter as a setback to that progress. Leadership said they are focused on getting a just contract, not just a quick deal.
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"I would be happy to solve this and go back in tomorrow, but we didn't get this far to give up on things that will make our schools better," Sharkey said.
"Delay is not our friend. We have to move expeditiously, if the CTU need additional help have at it, but we need to have our people at the bargaining table moving ahead," Lightfoot said.
The mayor said the size of CTU's 40-person bargaining team has slowed things down. The union said it will have a smaller team at the table when talks resume in the morning.
The mayor and CPS released a statement Monday night, saying:
"Tomorrow, for the fourth straight school day, students from throughout the city won't be participating in the athletic competitions they've earned the right to compete in, won't be preparing their college applications with trusted school staff, and won't be in classrooms with the teachers who hold the keys to their success. We must fix that immediately and end this strike. Real progress has been made on the key contract issues that CTU identified, and written proposals to boost staffing and support overcrowded classrooms have been exchanged. We were encouraged today by the improved pace of bargaining and substantive discussions on key issues, so it is now deeply concerning to hear that CTU is pulling members of its bargaining team away from the negotiating table tomorrow at this crucial juncture. Our full team will be ready first thing tomorrow morning to continue working toward the fair contract our teachers, students, and families deserve."
CTU said pay is still an issue especially for the lowest paid school workers and special educators and even veteran teachers. They are also fighting for more teacher prep time.
STRIKING TEACHERS DEMONSTRATE ON NEAR WEST SIDE
In what has become a daily afternoon occurrence, teachers and their supporters gathered for a rally and march. This time several hundred, if not thousands, of teachers and supporters met at Union Park in West Town and then marched around the Near West Side.
The march took them to locations including SEIU headquarters, McDonald's headquarters in the West Loop, and some development areas as they tried to draw attention to what they said are city investments that enrich developers. The union said they want those same investments for neighborhood schools.
The union said they are willing to demonstrate every day and said the marches have been effective in driving home their message at the bargaining table.
Outside of Gray Elementary School, teachers talked about their working conditions and what they are hoping for.
"We have class sizes that are way over limits. The legal limits in a self-contained classroom is 13, I've sat at 18 one year. I need the support staff in my classroom, it is impossible to do that on my own," said Special Education teacher Kaitlyn Jensen.
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As they walked into Malcolm X College to continue the fifth day of negotiations, a group of frustrated parents gathered at City Hall to urge teachers to end this strike.
"Could they have not kept negotiating while the kids are in school?" said Kay Winding with the Black Community Collaborative.
CPS tweeted classes and after school activities are canceled Monday. School buildings will be open for students who need a safe place to stay during the day.
Twenty-six thousand CPS teachers and 8,000 support staff workers including custodians, special education assistants and bus aides are on strike. It is the first CPS teacher strike since 2012.