Was the U.S. Constitution, as the South Carolinian states-man John C. Calhoun believed, a pro-slavery document, or did it, as President Abraham Lincoln argued, deny slavery a place in national law and point toward abolition? Although most Americans outside the academy would assume that Calhoun was wrong and Lincoln right, the contrary view has gained so much ground among academics in recent years that Wilentz’s qualified endorsement of Lincoln’s interpretation is both bracing and brave. Wilentz’s thoroughly researched argument serves as a useful example of solid scholarship and effective writing on a sensitive topic. It also highlights the growing importance of historians to legal studies as the federal bench fills with originalist interpreters of the Constitution. Wilentz is not an originalist himself, but the historical methods he employs here to uncover the intended meaning of the Constitution are exactly those that originalists use. Lawyers and jurists looking to develop arguments that will impress conservative judges would be well advised to study the tools Wilentz deploys to such great effect.