This essay examines a major change that has occurred in recent years with regard to the relationship between the president and the bureaucracy. It is a change that relies on a greater use of the president's unilateral powers to influence the bureaucracy. It is based on a theory of presidential power that is striking in its scope and implications: the unitary executive theory. In many respects, the theory fundamentally changes the nature of presidential–bureaucratic relations, yet it has received scant attention in scholarly journals. Examination of its potential impact is long overdue.