The foundations of constitutional theory

Normative constitutional theory asks at least two distinct questions: How should judges and other officials approach constitutional decisionmaking? And what counts as a good reason-or "normative foundation"-for adopting a particular approach? The two questions are obviously related, but the first has filled libraries while discussion of the second has been largely unsystematic and ad hoc. There is no well-recognized taxonomy of the types of reasons on which an approach to constitutional decision-making might be premised. Nor is it widely appreciated that competing approaches might rest on the same type of normative foundation or that multiple normative foundations might be invoked to support a single approach to constitutional decision-making. This Article proposes a taxonomy organizing the normative foundations of constitutional theory into four distinct categories: metaphysical, procedural, substantive, and positivist. This taxonomy clarifies that theoretical disagreement can concern the proper approach to constitutional decision-making, what counts as a good reason for adopting a particular approach, or both. It also permits analysis of the attractions and limitations common to each type of normative foundation, revealing significant points of overlap between apparently divergent approaches. Positivist originalism, for instance, may in some respects share more in common with positivist common-law constitutionalism than with metaphysical originalism. These points of overlap should serve as the basis for new and more productive discussion among theorists who have previously considered themselves completely at loggerheads.