The work of the National Institute for Clinical Excellence, an agency which has recently been created by Tony Blair's Labour government to provide guidance on best clinical practice to the National Health Service, has generated considerable controversy in the United Kingdom. It has been argued that the role which the institute plays in appraising cost effectiveness,especially of expensive new health technologies, constitutes explicit,national rationing. Although the employment of scientific and evidence-based criteria as the basis of decisions might have been expected to secure legitimacy for the institute—even when its recommendations have the effect of denying access to a particular treatment—the reaction to much of its work so far indicates that this goal has not been fully achieved. While alterations to structure and procedure may be considered as possible means of addressing the agency's difficulties, such proposals are not without problems. Consequently, in the final analysis, the British example may serve as a demonstration that the inherently political nature of priority-setting in health care precludes any easy technocratic solution.