Abstract
Normative political theorists have been growing more and more aware of the many difficult questions raised by the discretionary power inevitably left to public administrators. This article aims to advance a novel normative principle, called ‘principle of restraint’, regulating reform of established administrative agencies. I argue that the ability of public administrators to exercise their power in accordance with the requirements of public reason is protected by an attitude of restraint on the part of potential reformers. Specifically, they should refrain from any reform of an administrative agency that involves a switch to a considerably more loosely interconnected system of values underlying the work of that agency. To illustrate the importance of the principle of restraint, I examine a case from British health policy, showing that a recent reform of the National Institute for Health and Care Excellence well exemplifies the serious problems brought by any violation of that principle.