This chapter examines Irish nationalism in the context of the debate over slavery and abolition. It focuses on the figure of Daniel O'Connell. O'Connell was by reputation Ireland's liberator; he certainly was the most authoritative and charismatic voice of the emerging Irish Catholic nation of the early and mid-nineteenth century. He was also an outspoken opponent of slavery—in fact, one of the most powerful antislavery voices in all of Europe. Seeing the White Republic, and Irish Americans, through O'Connell's eyes requires us to explore the complex circumstances that confronted Irish immigrants in the United States and to understand why they would not—and to some degree could not—embrace his antislavery views. What is perhaps most remarkable about O'Connell, though, is not his success or failure in this regard but his attempt to construct an Irish identity that required opposition to slavery and other forms of oppression as one of its essential components.