As the expanding United States grappled with the question of how to determine the boundaries of slavery, politicians proposed popular sovereignty as a means of entrusting the issue to citizens of new territories. Christopher Childers now uses popular sovereignty as a lens for viewing the radicalization of southern states' rights politics, demonstrating how this misbegotten offspring of slavery and Manifest Destiny, though intended to assuage passions, instead worsened sectional differences, radicalized southerners, and paved the way for secession.

In this first major history of popular...