Later, as the anti-slavery movement gained momentum and began to threaten the economic basis of the South's prosperity, most white Edgefieldians, like most white South Carolinians, embraced this sectionalism. National unity was again threatened in 1850 when many leaders throughout the South began to speak of secession. The 1856 caning of Senator Charles Sumner by Edgefield Congressman Preston Brooks on the floor of the United States Senate galvanized the nation and set South Carolina on a course for secession and Civil War. By the fall of 1860 when Abraham Lincoln was elected President, all but a few Edgefield citizens were convinced that the time had come for the South to go its own way. A convention was called and Edgefield's delegation joined in the unanimous declaration of secession.