The Nullification Crisis of 1832-1833, when the state of South Carolina challenged the doctrine of states' rights by refusing to pay national tariffs, was the major crisis of Andrew Jackson's presidency. Ellis shows how his swift, decisive response reaffirmed the primacy of the national government and helped to shape Jacksonian democracy.

"An outstanding addition to the literature on Jacksonian democracy and should become a standard source on the nullification crisis....Ellis has given a fresh interpretation to a familiar topic and has offered a convincing reassessment of the broader significance of the nullification crisis in Jacksonian democracy."--History: Reviews of New Books "A superb study, adding new information and insights into our understanding of the Nullification Controversy of 1832-1833. It is richly textured with valuable details on both the national and state levels and quite outstandingly demonstrates a sophistication of understanding about the political maneuvering that occurred."--Civil War History "Makes a significant contribution to political and constitutional history."--The Historian "Extensively researched and thought-provoking....[Ellis's] discussion has rich detail and much novelty....Its strength lies in its reconstruction of a dramatic historical moment with an informative emphasis upon its constitutional importance."--Georgia Historical Quarterly "A fine study by a masterly political historian."--Merrill D. Peterson, University of Virginia "Ellis has done a superb job in exploring and uncovering new dimensions of an old and often treated topic...The Union at Risk makes a major contribution to historical literature."--James Roger Sharp, Syracuse University "By tracking the Nullification Crisis to a new depth in the politics of the states Ellis shows how the states' rights bulwark of Jefferson's yeoman republic became the bulwark of slavery."--Charles Sellers, University of California, Berkeley "A major addition to the scholarship of the Jackson period."--CHOICE