This week's featured article at the Sobel Wiki is on George Vining, the seventh President of the United States of Mexico, and the last to be chosen by Constitutional means for 23 years.
If you were looking for evidence that Robert Sobel was writing For Want of a Nail on the fly, with no larger plan in mind, George Vining would probably be exhibit number one. Sobel introduces Vining in the penultimate paragraph of chapter 16 "The Kinkaid Interlude." President Kinkaid has been assassinated, and the Mexican Senate is deadlocked on the choice of a successor. Vining, "an unambitious man," emerges as a compromise candidate who reluctantly agrees to serve out the remainder of Kinkaid's term of office "for the sake of unity." Sobel goes on to say that the real power in the government would be exercised by Vining's Secretary of State, and that Vining surprised the nation by choosing Thomas Rogers, the leader of the opposition Liberty Party, for the position.
Sobel ends the chapter on that note, then takes up events in Europe in chapter 17 "The Bloody Eighties", and events in the Confederation of North America in chapter 18, "An Age of Renewal." It is only in chapter 19 "The Crisis of Mexican Republicanism" that he returns to Mexico. And it is clear that by then Sobel had changed his mind about what direction he wanted Mexican history to take. George Vining, the reluctant unity candidate, is replaced by a ruthless figure who will turn Mexico into a police state. Thomas Rogers, the power behind the throne, is replaced by a hapless opposition leader who will foolishly acquiesce in the destruction of representative government. And lastly, Sobel introduces us to Benito Hermión, son of former president Pedro Hermión, and the man who will seize control of Mexico and make himself dictator by the end of the chapter.
Sobel didn't even go back and rewrite the end of chapter 16 to make it conform to chapter 19. The result is one of the most severe inconsistencies in the whole book.