CHICAGO (CBS) — A teachers’ strike is going ahead in Chicago on Thursday, after Chicago Teachers Union delegates voted unanimously to go ahead with a walkout.

CTU President Jesse Sharkey announced the decision Wednesday evening.

As CBS 2’s Tara Molina reported Wednesday night, Mayor Lori Lightfoot expressed disappointment at the move as she spoke ahead of the teachers’ union’s official announcement.

“I hope this work stoppage will end soon,” the mayor said.

“We need to get back to the bargaining table and get a deal done so we can all proceed, that’s in the best interest of our children, our families, our community and our city,” Lightfoot said.

On Wednesday afternoon, Chicago teachers lined up to grab picket signs ahead of the official strike announcement.

“We are here fighting for our students. We would much rather be in the classroom with them, but we know that we will be in front of our buildings fighting for what they deserve,” said said teacher Linda Perales. “Because they deserve special ed teachers, they deserve librarians, they deserve music teachers, they deserve art teachers, they deserve counselors. They deserve this and we are fighting for it.”

Sharkey later said the strike approval came unanimously over two major points – class sizes and better staffing.

“I have 30 students in my classroom – half first grade, half second grade Twelve of those students are special needs that we know of. Three of those students require one-on-one aid. One of those students is wheelchair-bound. And I’ve only been provided with one aide,” said teacher Jesse McAdoo. “Those are my teaching conditions, and if my teaching conditions are terrible, it means my students’ learning conditions are terrible.”

“Twenty-five years and it’s the same thing. When I came into this system, they said the teachers were no good and I said, well, I’m going to make a difference. I’m going in,” said teacher Moselean Parker. “Here it is 25 years later, because we stand, because we want a smaller class size, we want social workers, we need nurses, we need clinicians.”

As CBS 2 Political Investigator Dana Kozlov reported, the walkout will go ahead officially at midnight. But even before talks ended, Mayor Lightfoot said she was not expecting any last minute changes and pre-emptively canceled classes for Thursday.

Chicago teachers said a big sticking point in the contract negotiations is a need for smaller class sizes and better staffing. And they want it in writing. The city is offering the teachers a 16% raise over a five-year contract, but teachers propose a 15% raise over three years.

“Most marriages don’t last five years, many marriages, and I don’t like this contract enough to marry it,” Sharkey said.

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On Wednesday morning, the mayor said the city agreed to give them that. But Lightfoot said CTU kept bringing up additional bargaining issues. One included wanting to shorten instructional time by 30 minutes in the morning.

That is something Lightfoot said will never happen.

She also said they want to get paid out for unused sick days. Requests, she argued, will add another $2.5 billion per year to CPS’s annual budget.

“We value our school workers and educators who make our schools successful. We value the workers who make our parks the gyms that they are. Honoring that value is who I am and what I stand for,” Lightfoot said. “But I also must be responsible to the taxpayers.”

Earlier in the day, Lightfoot said the union had made it clear they were hitting the picket lines Thursday no matter what.

“In light of that declaration, we believed that we owed it to the parents and students of CPS to give them as much advance notice as possible that the CTU has decided to strike,” Lightfoot said.

That was what led Lightfoot and CPS CEO Janice Jackson to cancel classes even before the strike announcement – helping parents plan child care and in a sense, launching a preemptive strike.

“It’s pitiful that we’re at this point,” said Chicago Teachers Union Vice President Stacy Davis Gates.

As to the insinuation that the union planned to strike all along, Gates said, “That’s petty.”

But there is nothing petty about a walkout and its impact on 360,000 Chicago Public Schools students. The mayor said she has done everything possible to help keep this from happening, addressing issues such as class sized, staffing, and nurses on paper.

“Without question, the deal that we put on the table is the best in the Chicago Teachers Union’s history,” Lightfoot said.

CTU strongly disagrees.

“There is a gross disconnection between what she says and what’s on the table,” Gates said.

The union also disputed Mayor Lightfoot’s claims about the specifics of the offer and the demands, saying when it comes to class sizes, the offer on the table is the same as what’s in the current contract.

And when it comes to staffing, the city doesn’t have anything in writing.

As for reducing instructional time, they said teachers often prep at home after their workday ends. So they want more prep time and to be paid for it.

“The goal line was her campaign pledges. So everything that has been in every proposal that we have offered the Board of Education is everything that she has promised to give our students when she was a candidate running for mayor. So moving the goal post, I think that’s what she’s done,” Gates said.

So who is telling the truth – or could this simply be a struggle for power? Such a thing is not uncommon in negotiations, but problematic when there’s possible collateral damage – even if temporary.

“If she cannot land a deal with teachers for public schools in Chicago, then you have to question her ability to get work done in this city,” Gates said of Lightfoot.

“This isn’t about me. It’s not about a power struggle. It’s about our kids and we can’t lose sight of that.”

RELATED: Chicago Teachers’ Strike Is 7th Of Past 40 Years

The circumstances behind the strike this year is remarkably similar to the one that transpired seven years ago. In 2012, the Chicago Teachers Union went to the picket line for a week after talks with the city broke down.

Then as now, there was a new mayor at the time – and it is now Mayor Lightfoot’s first CTU contract negotiation as it was Mayor Rahm Emanuel’s first in 2012.

“This is not an autocracy. This is a democracy. People made a vote because she said that (Mayor Lightfoot) was going to transform,” said Chicago Teachers Union Vice President Stacy Davis Gates. “We are holding her accountable.”

Both in 2012 and today, months of talks culminated in a last-hour impasse, with both sides painting very different pictures of progress. Issues deemed as non-negotiable by the city, such affordable housing, were pushed by the CTU.

But this time, Mayor Lightfoot said the city has been listening to the union.

“Beyond compensation, we have offered more than 80 proposed changes to the contract on issues requested by the union,” Lightfoot said.

That includes sanctuary school protection, limiting privatization, and support for oversize classes.

“To say that you have offered a proposal that respects what we are asking for; to say that you’ve bent over backwards, and it’s the same proposal – not even; less than what’s in there now – it’s absolutely ridiculous,” Gates said.

Yet according to CPS, enrollment has declined – from 396,683 students in 2015 to 361,314 in 2019. Lightfoot said the city’s finances are still shaky.

“Our offer to teachers and support staff is responsible to taxpayers,” Lightfoot said.

“The taxpayers have subsidized the development of skyscrapers and cannot give black children on the South Side a lower class size,” Gates said.

So now that a strike is a done deal, what is it going to take to end it?

“When someone comes with good faith and we can earnestly say that looks like a solution to us, that’s really going to make conditions better – not just something that’s going to appease us and get us back in the door,” Sharkey said.

Meanwhile, with school now canceled on Thursday, the looming strike has many parents trying to figure out where to send their kids Thursday. A total of 360,000 students are affected.

RELATED: What Is The Contingency Plan For Children If Teachers Strike On Thursday?

Here’s what you need to know:

*There won’t be any classes or after school activities, but buildings will be open, so kids have somewhere to go.

*Breakfast and lunch will be served but there won’t be any bus service.

*Other agencies are getting ready for an influx of students if teachers walk out. The neighborhood Boys and Girls Club is preparing to have up to 200 hundred additional students.

It costs $60 a day, but the fee can be waived for families who are part of federal or state programs.

*CTA rides will be free for students.

*The Salvation Army has three sites ready to provide programming for kids during the school day.

*The Freedom Center in Humboldt Park will serve breakfast, lunch and dinner and is free.

*The Chicago Lawn Corps can hold up to 50 kids, and is also free. The Kroc Center in West Pullman will cost $15 a day, but can serve up to 200 kids.

Stay with CBS 2 through Wednesday’s vote. To see the sticking points and where both sides stand visit cbschicago.com/teachersstrike

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