Among the thousands of political refugees who flooded into the United States during the late-eighteenth and early-nineteenth centuries, none had a greater impact on the early republic than the United Irishmen. They were, according to one Federalist, "the most God-provoking Democrats on this side of Hell." "Every United Irishman," insisted another, "ought to be hunted from the country, as much as a wolf or a tyger." David A. Wilson's lively book...