What is America, and what is an American? If anything binds us together across space and time, it is our ideals and the stories we tell about our pursuit of them. From the beginning, we set ourselves against Europe’s hierarchies. We exalted democratic government, equality of opportunity and individual freedom. We conceived of our experiment as “the last best hope of earth,” in Lincoln’s words.

But ideals don’t live in a vacuum; they take root in the soil of institutions. Beginning with our first experiments in self-government, the dissonance between our ideals and our institutional practices–especially the tolerance and extension of slavery–created tensions that finally tore us apart.