The Center Cannot Hold — Harry Turtledove

The year is 1924. In the United States, the Socialist Party, led by Hosea Blackford, battles Calvin Coolidge to hold on to the', Powell House in Philadelphia. The Confederate States, victorious in the War of Secession but at last tasting defeat in the Great War, suffer poverty and natural calamity. The Freedom Party promises new strength and pride, but if its chief seizes the reins of power, he may prove a dangerous enemy for the hated U.S.A. By the time the 1920s come to a close, catastrophe will cast a pall across the continent--and in a world of simmering hatreds, shattered lives, and pent-up violence, the center cannot hold. And for a powerful nation, the ultimate shock is yet to come. . . .