Yale historian David Blight examines how emancipation actually happened during the Civil War, tracing the shift from a war to preserve the Union into a war that destroyed slavery. This session, part of his DeVane Lecture Series course on slavery's legacies at Yale, covers the Emancipation Proclamation's legal and political mechanics, the role of enslaved people who fled to Union lines, and the military necessity arguments that pushed Lincoln toward abolition. Blight connects battlefield developments to the political fight in Washington, showing emancipation as a gradual, contested process rather than a single decree. The lecture sits within a broader course asking how the Civil War's constitutional and racial legacies still shape American institutions, using primary sources and close narrative to walk through the war years as a hinge point for the nation's understanding of freedom and citizenship.