As president, Abraham Lincoln experienced a fundamental change in his thinking that transformed America. Lincoln took office in March 1861 as a moderate Republican — morally and politically opposed to slavery, particularly its extension into the western territories, yet willing to accept its presence in the South in order to maintain the Union as established by the Founding Fathers and governed by the Constitution. Lincoln retained this view even after several southern states seceded, telling them that they could return with slavery intact. When they failed to do so, Lincoln pursued war to force them back into the Union, not to abolish slavery.
During the war, however, Lincoln radically changed course, taking a series of steps that ended slavery and opened the door to a future of a biracial democracy. How can this be explained? As with any great change, the reasons are varied and complex but they all essentially relate to the Civil War — an unprecedented crisis that grew larger, deadlier, and costlier than anyone expected. It was, as Lincoln described, “the fiery trial through which we pass” — a searing experience that challenged and changed everyone who experienced its mighty forces. Lincoln’s trial began with the shock of southern secession and continued with a series of military defeats, eroding public morale, thousands of slaves seeking their own freedom behind Union army lines, and unrelenting criticism from all sides. Together, these forces prompted Lincoln to abandon long-held views and courageously chart a new course of action, one that ultimately abolished slavery, saved the nation, and gave all Americans a new birth of freedom.