The National Defense Service Medal (NDSM) was first intended to be a "blanket campaign medal" awarded to service members who served honorably during a designated time period of when a "national emergency" had been declared during a time of war or conflict. It may also be issued to active military members for any other period that theSecretary of Defensedesignates.
To date, the NDSM has been awarded for four specific time periods, which roughly correspond to the Korean War (1950–1954), Vietnam War (1961–1974), Gulf War (1990–1995), and the Global War on Terrorism (2001–2022).
Eligibility for the NDSM was expanded by executive orders issued in 1966 (EO 11265), 1991 (EO 12776) and 2003 (EO 13293).
Executive Order 11265, dated January 11, 1966, extended eligibility for the NDSM to service members "who served during any period after December 31, 1960, which the Secretary of Defense designates as being a period for which active military service merits special recognition." The closing date of this period of eligibility was later set at August 14, 1974 by a letter from the Assistant Secretary of Defense for Manpower and Reserve Affairs, subject: Termination of Eligibility for the National Defense Service Medal, dated June 30, 1974.[3]
The NDSM was again authorized by a memorandum, dated 20 February 1991, from Secretary of DefenseDick Cheneyfor active service on or after 2 August 1990 with no termination date established.[3]Executive Order 12776 of October 8, 1991 extended eligibility for the NDSM to members of the Reserve Components during the period of theGulf War. This eligibility period was later defined as from August 2, 1990 to November 30, 1995.
A memorandum from the Office of the Deputy Secretary of Defense, dated April 26, 2002, authorized the reinstatement of the NDSM for all active duty personnel retroactive to September 11, 2001. Executive Order 13293, dated March 28, 2003, amended EO 10448 to extend eligibility to all Selected Reserve personnel (i.e. actively drilling members of the reserve components to include the National Guard). As EO 13293 amended the EO which established the NDSM, this made Selected Reserve personnel from all previous eligibility periods eligible for the NDSM, to include those who served during the Korean and Vietnam eras.
On August 30, 2022, Secretary of DefenseLloyd Austinissued a memorandum stating that issue of the NDSM would be suspended after December 31, 2022.[4]

