Chicago Teachers Union backed Toni Preckwinkle for mayor of Chicago, donating nearly $300,000 to her campaign. But Lori Lightfoot won – and now CTU is on strike for the third time in seven years despite her generous offer.

Chicago Teachers Union backed Toni Preckwinkle for mayor of Chicago, donating nearly $300,000 to her campaign in 2019. But Lori Lightfoot won – and now CTU is threatening to go on strike despite being offered a generous deal.