At this very moment, hundreds of U.S. nuclear warheads and bombs are poised to strike targets in Russia and elsewhere. Despite the demise of the Soviet Union in 1991—and thus the end of the cold war policy of mutually assured destruction—the U.S. maintains a stockpile of roughly 10,000 nuclear weapons. Russia, China, France, India, Israel, Pakistan and the U.K. are now all U.S. allies or, at worst, nonbelligerent competitors. All but Russia possess only limited nuclear arsenals. North Korea and Iran, whose relations with the U.S. are more strained, do not yet have the capability to inflict massive nuclear harm on this nation. Indeed, the most pressing nuclear hazard appears to be a “dirty bomb”—a conventional bomb packed with radioactive material—or a small nuclear explosive. A massive nuclear arsenal may provide little deterrent against the use of such weapons by terrorists or nonstate entities.

As part of its obligations under the Moscow Treaty on Strategic Offensive Reductions, the U.S. plans to reduce its total number of active nuclear weapons to between 1,700 and 2,200 warheads and bombs. At the same time, the U.S. Department of Energy and the Department of Defense, worried that aging warheads may not operate optimally after years of storage, want to replace some of them. First on the list is the W76, which makes up a third of the available warheads; the oldest W76s will reach the end of their 30-year life span in 2008. An individual W76 nuclear explosive generates 100 kilotons of force when detonated, equal to 100,000 tons of TNT; it is designed to obliterate “soft targets,” such as ports, garrisons and factories.