His work especially relies on using the Freedom of Information Act to compel US government agencies to release documents. He maintains an on-line overview of the number of nuclear weapons in the world,[5] and writes frequently on the FAS Strategic Security Blog.[6]
He is critical of the development and deployment of nuclear weaponry by the United States, the United Kingdom, and France.[7] In 2005 he discovered a draft document on a Pentagonwebsite that proposed a change in U.S. nuclear doctrine to include the possibility of a preemptive nuclear strike. Even though SecretaryRumsfeld had not approved the change, its publication provoked a reaction from some members of Congress.[8] In 2022, US President Joe Biden announced that the United States would use nuclear weapons as a first strike in "extreme circumstance," without any objection from Kristensen or the Federation of American Scientists.[9]
^Pincus, Walter (11 September 2005). "Pentagon Revises Nuclear Strike Plan (Strategy Includes Preemptive Use Against Banned Weapons)". The Washington Post. ISSN0190-8286. OCLC2269358. Archived from the original on 6 March 2008. Retrieved 6 December 2019. Hans M. Kristensen, a consultant to the Natural Resources Defense Council, who discovered the document on the Pentagon Web site, said yesterday that it "emphasizes the need for a robust nuclear arsenal ready to strike on short notice including new missions." Kristensen, who has specialized for more than a decade in nuclear weapons research, said a final version of the doctrine was due in August but has not yet appeared. "This doctrine does not deliver on the Bush administration pledge of a reduced role for nuclear weapons," Kristensen said. "It provides justification for contentious concepts not proven and implies the need for Robust Nuclear Earth Penetrator (RNEP)."
