In the 1960s and early 1970s, U.S. policymakers maintained a complex effort to limit the dissemination of gas centrifuge technology for enriching uranium, which they saw as an inherent nuclear proliferation risk. Recognizing that controls could not stop scientific research and development, U.S. officials nevertheless believed the overseas development of gas centrifuge technology could be slowed. To prevent further dissemination overseas, the United States supported cooperation with European allies that were already developing the technology. Cooperation involved implementation of secrecy and export controls, although a U.S. initiative to include Japan failed because nuclear secrecy was incompatible with Japanese law. The United States tried to deflect Japan's interest in the gas centrifuge by offering to share an alternative technology, gaseous diffusion, for enrichening uranium. That initiative failed, but the U.S. government remained committed to keeping enrichment technologies under secrecy controls.

In early 1969 President Richard Nixon and his national security adviser, Henry Kissinger, received a brie fing on the U.S.nuclear war plan, the Single Integrated Operational Plan (SIOP). Appalled by the catastrophic scale of the SIOP, Nixon and Kissinger sought military options that were more credible than massive nuclear strikes. Participants in the Air Force Nuclear Options project also supported more flexible nuclear war plans.Although Kissinger repeatedly asked Defense Department of ficials to construct limited options, they were skeptical that it would be possible to control nuclear escalation or to introduce greater flexibility without weakening the SIOP.Interagency studies presented a mixed verdict about the desirability of limited options; nevertheless, continued White House pressure encouraged Secretary of Defense Melvin Laird to sponsor a major review of nuclear targeting.In 1972 the Foster panel developed concepts of limited, selective, and regional nuclear options that were responsive to Kissinger's interest in credible nuclear threats. The Foster panel's report led to the controversial “Schlesinger Doctrine” and further efforts to revise the SIOP, but serious questions endured about the whole concept of controlled nuclear warfare.