American constitutional law is at a crossroads. In a major new interpretation of the Constitution, Cass Sunstein offers a clear account of our present dilemmas and shows where we might go from here.

As it is currently interpreted, the Constitution is partial, Sunstein asserts. It is, first of all, biased. Contemporary constitutional law treats the status quo as neutral and just, and any departure as necessarily partisan. But when the status quo is neither neutral nor just, Sunstein argues, reasoning of this sort produces injustice. The Constitution is also partial in another sense:...