In recent times, some scholars have discussed a new way in which to view presidential power, one that considers the president's ability to effect policy change unilaterally without the consent of Congress or the courts. The limits of presidential power can still be defined essentially by the ability and willingness of Congress and the courts to constrain it. However, the use of national security directives poses particular challenges to the abilities of both Congress and the courts to constrain effectively the president's power to act unilaterally in setting public policy. Drawing upon continuing research, this article offers some preliminary observations and insights into the role of national security directives and how they have contributed to shaping U.S. national security policy.