This chapter provides an understanding of how an Anglo-Atlantic antislavery movement and the prospect of emancipation in the British West Indies unleashed a growing debate on its impact on the United States. This followed from a history of fears of foreign “moral contagion” on the issue of slavery, and similar domestic anxieties — including slave rebellion in Virginia and an emergent abolitionist movement. Highlighting anti-abolitionist riots in New York in 1833 and 1834, it situates these events within trepidations of national and racial boundary crossings that grew out of anxieties over British Emancipation in its Caribbean colonies and its influence on America.