Yale historian David Blight covers the Civil War's turning point, when Confederate military success gave way to collapse. Part of his DeVane Lecture Series course "Can It Happen Here Again? Yale, Slavery, and Legacies," this session traces the war's shifting momentum, from early Confederate victories through the political and military decisions that led to Southern defeat. Blight situates the battlefield narrative within the larger constitutional and moral stakes of the war, treating emancipation and the fate of the Union as inseparable from military outcomes. He draws on primary sources and the historiography of the period to explain why Confederate ascendancy proved temporary and what its collapse meant for the reconstruction of American political life. The lecture is one installment in a longer course examining slavery's legacies in American institutions, but this class centers on the war's military and political arc rather than contemporary politics.