In the post Cold-War world, and especially in the aftermath of the attacks of September 11, 2001, the U.S. threat perception has been totally reversed. The United States discounts any nuclear threat from Russia, despite the continued existence of a strong Russian strategic nuclear arsenal. Americans see no plausible source of armed conflict between themselves and Russia, and thus perceive no nuclear threat, except, perhaps, from miscalculation. This lack of concern is demonstrated by the 2001 Nuclear Posture Review conclusion that the United States no longer needed to plan its nuclear forces as if Russia presented an immediate threat, by the lack of U.S. interest in including traditional crisis stability measures in the 2002 Treaty of Moscow, and by the indifference with which the United States has responded to Russian hints that it might deploy multiple warheads on the Topol-M (SS-27) intercontinental ballistic missiles.⁷

China remains of concern, at least for some analysts and officials, because of the fear of a potential nuclear confrontation over Taiwan. These analysts fear that China would use its nuclear weapons in non-traditional ways, for example by using high-altitude bursts to generate electro-magnetic pulse as a counter to U.S. naval superiority. The United States has not, however, taken any action in response to this concern. Other analysts fear that China is on the verge of significant modernization that could increase the future nuclear threat to the U.S. homeland. The Nuclear Posture Review call to dissuade potential adversaries from trying to match U.S. capabilities clearly was drafted with China in mind. This policy has not, however, had any practical impact.

During the Cold War, nuclear proliferation was seen as a threat to international stability and a possible long-term threat to American security. In the post-Cold War world, proliferation, above all by Iran and North Korea, is seen as a direct, near-term threat to America. In the U.S. system, true policy is reflected not in rhetoric but in the budget. The U.S. deployment of ballistic missile defenses, narrowly designed to counter ballistic missiles from Iran and North Korea (although having an innate capability that concerns China and Russia) is a reflection of the degree to which Americans see nuclear-armed Iran or North Korea as a threat. While diplomacy is America’s preferred method of reducing this threat, defenses—rather than deterrence—is seen as the appropriate course if diplomacy fails. This is not because such states are “undeterrable;” in principle deterrence can operate on any state. But many Americans are concerned that we may not understand the values, motives and decision-making style of the North Korean and Iranian leadership well enough for deterrence to be effective.