National Security Decision Memorandum

National security directives are presidential directives issued for the National Security Council (NSC). Starting with Harry Truman, every president since the founding of the National Security Council in 1947 has issued national security directives in one form or another, which have involved foreign, military and domestic policies. National security directives are generally highly classified and are available to the public only after "a great many years" have elapsed. Unlike executive orders, national security directives are usually directed only to the National Security Council and the most senior executive branch officials, and embody foreign and military policy-making guidance rather than specific instructions.

Presidents have issued such directives under various names.

National security directives were quite different in the early period of the Cold War. A 1988 General Accounting Office (GAO) investigation into national security directives left out the directives from the Truman and Eisenhower years because "they were not structured in a way to allow categorization." The study nevertheless made note of two types of directives. The first was "policy papers" which could contain policy recommendations, in which case the president might decide to approve the policy by writing his signature. A famous example of such a policy paper is NSC 68. GAO also noted another type of directive called "NSC Actions", which were "numbered records of decisions that were reached at NSC meetings.

The Kennedy administration which took office in 1961 reorganized the NSC and began issuing National Security Action Memoranda (NSAMs). Many NSAMs were signed in Kennedy's name by National Security Advisor McGeorge Bundy, although Kennedy sometimes signed them personally.Lyndon B. Johnson continued issuing NSAMs where Kennedy left off, although issuing only 99 directives as compared to Kennedy's 273.

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