The Assistant Secretary of Defense for Global Strategic Affairs, or ASD(GSA), is a position in the Office of the Secretary of Defense that develops policy for the Secretary on countering weapons of mass destruction, nuclear forces and missile defense, cyber security and space issues. ASD(GSA) is currently tasked with three major congressionally mandated reviews: the Nuclear Posture Review, the Ballistic Missile Defense Review, and the Space Posture Review. In addition, GSA is the Defense Department's lead in developing the DoD's cybersecurity strategy, and for crafting the policy for the standup of the new Cyber Command. ASD(GSA) answers to the Under Secretary of Defense for Policy. Although ASD(GSA) is a recently configured office, its functional responsibilities can be traced back in part to a position eliminated in early 2008, the 'Assistant Secretary of Defense for International Security Policy'
The office also directs the Defense Technology Security Administration.