The Disunited States of America, Tor, 2006, is the fourth novel in the Crosstime Traffic series. It posits an alternate in which the United States did not reach the compromise of the bicameral legislative branch at the Constitutional Convention of 1787, and so continued to use the Articles of Confederation. After a few decades, the United States simply ceased to exist, and the various states became countries unto themselves. Many have a history of war with their neighbors. Beckie Royer travels to Virginia with her grandmother, Myrtle Bentley. So do Crosstime Traffic employees Justin Monroe and his mother. By chance, they meet. Shortly after, Virginia goes to war with its neighbor, Ohio. Biological weapons are used, stranding everyone.
A fragmented United States presents a wealth of possibilities, and Harry Turtledove scratches at the surface of them. Turtledove gives quick hints about some of the history of the continent, which countries resemble our own U.S. states geographically, how some familiar states are part of different entities altogether, and the like. For this reason, The Disunited States of America is arguably the most tantalizing and entertaining novel of the Crosstime Traffic series.
A similar idea is at the base of Michael Flynn's novella "The Forest of Time" (), also based on the alternate history scenario of the United States being stillborn and the various states going their separate ways (and often going to war with each other). Flynn's scenario in many ways resembles Turtledove's, but has the radical difference of assuming that the divided Americans would prove unable to subdue the Native American tribes to their west, supported by Britain, and that European settlement in North America would never extend far beyond the boundaries of the original thirteen colonies.