In Chicago Mayor’s Race, a Former Teacher Rises With Union Support

Brandon Johnson had a problem. In a crowded Chicago mayoral race full of established liberal politicians — a sitting congressman, the incumbent mayor, two City Council members — many voters had never heard of Mr. Johnson, a county commissioner from the West Side.

But he had something those other contenders did not: the Chicago Teachers Union.

Loved and loathed, the teachers’ union has emerged over the last dozen years as a defining voice on Chicago’s political left, putting forth a progressive vision for the city that extends well beyond its classrooms. After highly public fights with the last two mayors that led to work stoppages, union leaders see in Mr. Johnson a chance to elect one of their own, a former teacher who shares a goal of rebuilding Chicago by spending more on schools and social programs.