The revolution in Saint-Domingue reorganised mainland politics long before the Civil War settled anything, Horne argues, and the reorganisation ran through the people who fled it. Refugees carried their terror to North America and were absorbed into the slaveholding republic as useful allies: Judah P. Benjamin's father-in-law, who lectured audiences on African treachery, or Louis Tousard, who helped establish West Point after trying to suppress the 1791 revolt.

Haiti's existence sharpened an existential choice for slaveholders between retreating from slavery and risking everything, while arriving Frenchmen were courted as a demographic counterweight to the enslaved. Spain, Britain and the United States all watched Hispaniola nervously, and Grant's push to annex the Dominican Republic closed in 1871 a cycle that had opened in 1791.

A second thread follows the island's pull on mainland Africans, enslaved and free, for whom Haiti was a destination and an argument rather than a warning.