On Monday, Chicago will make history when Lori Lightfoot becomes the city’s first black female mayor. This victory sits alongside other firsts: her recent runoff against Toni Preckwinkle, a black woman and the president of the Cook County Board of Commissioners, and the 2016 election of Kim Foxx, a black woman, as the city’s top prosecutor.

Last year, when Rahm Emanuel announced he wouldn’t seek a third term as mayor, no one thought Ms. Lightfoot would win. In Chicago, activists have long understood that they may not get what they want in a mayor: It seemed to be an intractable problem, one among many others — like police violence, school closings, unfair wages.

But problems that once seemed intractable are changing. Ms. Lightfoot’s victory is part of a broader trend of black women emerging as the most influential political voices in the city. Black feminists, in particular, are securing progressive victories in a place where that long seemed impossible.