In 1840 William Henry Harrison, a member of the Whig party, was elected president of the United States, ending the forty-year stranglehold Jacksonian Democrats had on the White House and signaling the completion of a national two-party system. But even before Harrison's inauguration, interparty conflicts over slavery had overwhelmed both parties and they had begun to disintegrate.By the onset of the Civil War, the two-party system had become a mere mechanism for carrying out sectional interests. After the war, the parties struggled to once again become national organizations, but instead they found themselves beholden to powerful special interest groups. This book examines the social, economic and political factors that affected the parties during the sixty-year period, while delineating the personalities involved and the key campaign issues.