In the 1820s, Irish immigrants to the United States were a not unwelcome addition to a rapidly expanding nation. They were often Protestant, middle-class, and employable. By the 1830s and 1840s, a new dynamic was in play, and the Irish Catholics who crossed the Atlantic in staggering numbers were anything but welcome. Nativist violence against Irish Catholics assumed frightening proportions in the years before the Civil War, and America’s most famous Irish Catholic, John Hugh