Rosen looks at the legal justification and ramifications of the oft-forgotten or glossed over conflict between the United States and a variety of groups in Florida at the end of the 1810s. Frequently called the First Seminole War, the conflict involved the American military, under the leadership of Andrew Jackson, against Seminoles, Creeks, Spanish and British residents/merchants, and African-descended peoples. Rosen argues that this conflict was anything but minor in the course of American history, and the larger history of the law of nations. It was in this conflict, Rosen argues, that many of the justifications and understanding of the law of nations the United States and other European nations used in the later nineteenth and twentieth centuries (including the American defense of slavery/slave property, Indian Removal, and Manifest Destiny) were first clearly articulated during this conflict.
Rosen draws primarily from US Congressional records and printed legal treatises to explain two legal parts of the conflict. First, how the US's actions and justification for them drew on European/universalist ideas of the law of nations and thus helped the US claim a place as a nation that legally existed on the same terms as European nations. Second, how the US's actions and justification for them aided the defining of the United States along racial boundaries, with whites as citizens of the nation and all others as noncitizens. This racial division, frequently defined as civilized vs. uncivilized, would influence and alter the "universalist" law of nations as the nineteenth century continued (allowing justification for example American Western expansion and European Imperialism). In each way, the United States confirmed its sovereignty, something that had been in question since the Revolution.
Rosen's work is clearly articulated for even the non-specialist to understand complex legal concepts. She also successfully includes all the actors of the conflict, a difficult feat with there being so many of them and scant (truthful) evidence on the non-American actors. One criticism is that the work is repetitive, restating its argument over and over again--although with different evidence and new events/context. This work is a must read for those interested in legal history, foreign policy/affairs, American expansion, and antebellum America.