While Abraham Lincoln was taking center stage in a divided country, a political rival-turned-ally was exerting a major influence on national affairs. William Henry Seward, U.S. senator and former New York governor, lost the Republican Party nomination but aided Lincoln by touring the country on behalf of the Republican ticket. As Southern states prepared to withdraw from the Union, Secretary of State Seward sought to reunite the country. This biography explores Seward’s political power and the theory that, as president, he might have prevented the Civil War.