Between 1798 and 1801, in the middle of the Haitian Revolution, John Adams and Toussaint Louverture built a working diplomatic relationship, one that let white Americans back the liberty and self-rule of Saint-Domingue's people of color. The United States sent economic aid along with arms and munitions, and the conflict became the first occasion on which the U.S. Navy fought on behalf of a foreign ally.

Johnson, a historian and former diplomat, gives the alliance its first book-length treatment, setting out what these two revolutionary peoples wanted and how each maneuvered in a hostile Atlantic world. Leaders on both sides managed multiracial dealings in settings organized around slavery and racial hierarchy.

The diplomacy did not end American slavery, but it changed how slavery and race were argued about in the Atlantic world well into the twentieth century. No durable alliance followed, and the two republics went their separate ways.