This article merges the literature on national security decision making with scholarly work on presidential decision making. It examines ways in which national security decision-making structures are changed by international and domestic political forces as well as presidential management of the bureaucratic and organizational politics within the executive branch. Three decision-making case studies–the Carter administration's March 1977 Strategic Arms Limitations Talks II(SALT II) proposal, the Reagan administration's initial strategic arms reduction proposal of May 1982, and President Bush's speech of September 1991 that led to the Strategic Arms Reduction Talks (START) II–illustrate the dynamic and evolving nature of the national security decision-making process. The case studies suggest that presidents make modifications in their standard interagency processes for the deliberate purpose of achieving specific political goals. Adjustments in policy are the impetus for adjustments in process.