Nuclear Deterrence in the 21st Century Lt Col Stearns-Boles is the Air Force Fellow at Los Alamos National Laboratory and a Senior Developmental Education student in the Air Force's Fellowship program assigned to Air University/CADRE. Key words: Nuclear deterrence Issue. The 2006 Quadrennial Defense Report (QDR) included a vision of tailored deterrence as a capability for enabling homeland defense. This verbiage, and the new deterrence doctrine it foreshadows, indicates a series of U.S. security policy changes regarding how the U.S. will handle its adversaries in the 21st century. Policy makers must realize tailored deterrence is the right doctrine for the new world environment, and a role for nuclear weapons exists within tailored deterrence. Background. Nuclear deterrence is still applicable in today's security environment because it contributes to world stability. Nuclear weapons and their proliferation continued after the end of the Cold War.