Yale historian David Blight opens the third session of his DeVane Lecture Series course on slavery and its legacies by framing the semester's central question: can the fragile experiment of a pluralistic, constitutional democracy collapse the way the 1930s worried fascism might take hold, and what exactly is the "it" that threatens it here. He works outward from the course's premise that racial slavery was a defining force in American history, not a side issue, tracing how its endings and afterlives still shape political and constitutional life. Blight explains what he means by "legacy," setting up later classes that will examine slavery's ties to Yale itself, the Civil War, and the political, economic, and commemorative aftershocks that followed. The lecture is mostly conceptual scaffolding, laying out the stakes and vocabulary for a course built around a series of historical pivot points where American democracy's survival was genuinely in doubt.