Teacher unions

Mayor Lori Lightfoot speaks during a news conference at Chicago City Hall on Wednesday, Oct. 16, 2019. Lightfoot said classes would be canceled Thursday after determining that she can't accept the Chicago Teachers Union's demands, which she says would cost the city $2.5 billion it can't afford. Talks are expected to continue Wednesday. (Jose M. Osorio/Chicago Tribune via AP)

Mayor Lori Lightfoot speaks during a news conference at Chicago City Hall on Wednesday, Oct. 16, 2019. Lightfoot said classes would be canceled Thursday after determining that she can't accept the Chicago Teachers Union's demands, which she says would cost the city $2.5 billion it can't afford. Talks are expected to continue Wednesday. (Jose M. Osorio/Chicago Tribune via AP)

Mayor Lori Lightfoot speaks during a news conference at Chicago City Hall on Wednesday, Oct. 16, 2019. Lightfoot said classes would be canceled Thursday after determining that she can't accept the Chicago Teachers Union's demands, which she says would cost the city $2.5 billion it can't afford. Talks are expected to continue Wednesday. (Jose M. Osorio/Chicago Tribune via AP)

Mayor Lori Lightfoot speaks during a news conference at Chicago City Hall on Wednesday, Oct. 16, 2019. Lightfoot said classes would be canceled Thursday after determining that she can't accept the Chicago Teachers Union's demands, which she says would cost the city $2.5 billion it can't afford. Talks are expected to continue Wednesday. (Jose M. Osorio/Chicago Tribune via AP)

FILE - This Sept. 10, 2012 file photo shows Striking Chicago Public School teachers picketing as Mayor Rahm Emanuel visits with students taking part at the Safe Haven program during a teachers strike in Chicago. A threatened strike in 2019 by Chicago teachers would carry on the city's historically significant role in education labor disputes, including the 2012 strike cited by teachers around the country as inspiration for walkouts and other protests in recent years. That seven-day strike was a dramatic test of the Chicago Teachers Union's effort to force expanded negotiations into social issues beyond the typical give-and-take over pay and benefits. (AP Photo/M. Spencer Green, File)

FILE - This Sept. 10, 2012 file photo shows Striking Chicago Public School teachers picketing as Mayor Rahm Emanuel visits with students taking part at the Safe Haven program during a teachers strike in Chicago. A threatened strike in 2019 by Chicago teachers would carry on the city's historically significant role in education labor disputes, including the 2012 strike cited by teachers around the country as inspiration for walkouts and other protests in recent years. That seven-day strike was a dramatic test of the Chicago Teachers Union's effort to force expanded negotiations into social issues beyond the typical give-and-take over pay and benefits. (AP Photo/M. Spencer Green, File)

FILE - In this May 31, 2019 file photo, Mayor Lori Lightfoot holds a press conference at City Hall in Chicago. Teachers in Chicago, the nation's third-largest school district, are inching closer to a strike that could take place as early as next month. After rejecting the district's latest offer, Chicago educators are negotiating issues including pay, staffing shortages and class sizes. The labor dispute is one of Mayor Lori Lightfoot's first major tests after taking office this year. (Ashlee Rezin/Chicago Sun-Times via AP File)

FILE - In this May 31, 2019 file photo, Mayor Lori Lightfoot holds a press conference at City Hall in Chicago. Teachers in Chicago, the nation's third-largest school district, are inching closer to a strike that could take place as early as next month. After rejecting the district's latest offer, Chicago educators are negotiating issues including pay, staffing shortages and class sizes. The labor dispute is one of Mayor Lori Lightfoot's first major tests after taking office this year. (Ashlee Rezin/Chicago Sun-Times via AP File)

FILE - In this May 31, 2019 file photo, Mayor Lori Lightfoot holds a press conference at City Hall in Chicago. Teachers in Chicago, the nation's third-largest school district, are inching closer to a strike that could take place as early as next month. After rejecting the district's latest offer, Chicago educators are negotiating issues including pay, staffing shortages and class sizes. The labor dispute is one of Mayor Lori Lightfoot's first major tests after taking office this year. (Ashlee Rezin/Chicago Sun-Times via AP File)