The eighty-five famous essays by Hamilton, Madison, and Jay--known collectively as the Federalist Papers--comprise the lens through which we typically view the ideas behind the U.S. Constitution. But we are wrong to do so, writes David Brian Robertson, if we really want to know what the Founders were thinking.

In this provocative new account of the framing of the Constitution, Robertson observes that the Federalist Papers represented only one side in a fierce argument that was settled by compromise--in fact, multiple compromises. Drawing on numerous primary sources, Robertson unravels the...