Yale historian David Blight continues his DeVane Lecture Series course on slavery and American institutions with a session tracing the 1840s and 1850s crises that pushed the country toward civil war. He covers the Mexican-American War and the territorial gains it brought, the fierce debates over whether those lands would permit slavery, the Compromise of 1850 with its Fugitive Slave Act, and the Kansas-Nebraska Act of 1854, which reopened the question of popular sovereignty and shattered the old party system. Blight walks through the political maneuvering in Congress, the sectional anxieties over expansion, and the way each supposed settlement only deepened the conflict it tried to resolve. Delivered as a standard lecture hall talk with Blight speaking from notes, the class treats these episodes as hinge points where the country's commitment to slavery collided with its expanding borders, setting up the sectional rupture that follows in subsequent lectures in the course.