An Aug. 4 draft map of new Cook County commissioner districts (left) and the county’s “map room” [Alex Nitkin/The Daily Line]

The scramble to redraw Cook County’s 17 commissioner districts pushed closer to completion on Friday, as commissioners digested new block-level U.S. Census data that will help reshape their constituencies for the next decade. But the numbers added a fresh dose of uncertainty to the future of the county’s political landscape, especially in the county’s south suburbs, north shore suburbs and on Chicago’s Near Northwest Side.