CPS, Chicago Teachers Union trade barbs in dueling letters as talks for fall reopening sputter 3 weeks before the start of school

Lisa Williams, left, talks to Jennifer Johnson, center, and Stacy Davis Gates of the Chicago Teachers Union as they go door to door in the Hyde Park neighborhood of Chicago on Aug. 4, to talk about COVID-19 safety concerns as Chicago Public Schools prepare to reopen. (Terrence Antonio James / Chicago Tribune)