An unresolved issue in American constitutional governance is the role of public officials in a Madisonian scheme of separated institutions sharing power. Proposed answers range from broad delegation with reliance on expertise and professionalism to minimal delegation with formal checks on official discretion. In between are various pragmatic or realist views that accept discretion as both necessary and inevitable and offer normative principles of administrative conduct to guard against official abuse of power. None of these answers, however, satisfies criteria of constitutional legitimacy. The authors argue that such criteria can be derived by combining insights from traditional, normative literatures of public administration and from positive political theory and political economics. If the role of public managers is defined as maintaining a credible commitment to performing their duties pursuant to a precept of managerial responsibility that incorporates accountability, judgment, balance, and rationalit...