DJW credits Cermak with building the Democratic coalition in Chicago but read John R. Schmidt's "The Mayor Who Cleaned up Chicago" A political biography of William E. Dever and you'll see credit really belongs to another West Sider: Roger Sullivan.
...Sullivan had grown up in rural poverty near Belvidere, Illinois. He moved to Chicago in his late teens and found a job in a railway machines shop. He soon became interested in politics and moved up through the patronage ranks as he widened his circle of acquaintances. --Schmidt, page 19Schmidt writes on pages 49 through 54 about "The Sullivan Consolidation" during 1910 through 1920 when the various Democratic party factions were united (conquered really) by Sullivan. He concludes with this passage,
Roger Sullivan did not live to enjoy the fruits of his labor. The old boss died shortly before the Democratic National convention of 1920. Although he had been in declining health for some time, his passing came as a shock; he had been a prominent part of the Chicago scene for so long. Sullivan's only elected office had been as a probate court clerk in the 1890's, but the citizens of his city were aware that a political giant had moved among them. The honored him in the traditional way America commemorates her dead statesmen. They named a high school after him.The successors were George Brennan and Anton Cermak and the capstone Cermak's election as Mayor in 1931.
Yet, even with the death of its founding father, the Democratic organization scarcely missed a beat. The man dies, the machine lives on--Sullivan would have approved. His legacy had been a united, efficient Democratic party. Now his successors would have to put the capstone on his construction and realize full power. --Schmidt page 54