It is time for the U.S. government to admit that it has failed to prevent North Korea from acquiring nuclear weapons and intercontinental ballistic missiles that can reach the United States. North Korea no longer poses a nonproliferation problem; it poses a nuclear deterrence problem. The gravest danger now is that North Korea, South Korea, and the United States will stumble into a catastrophic war that none of them wants.

The world has traveled down this perilous path before. In 1950, the Truman administration contemplated a preventive strike to keep the Soviet Union from acquiring nuclear weapons but decided that the resulting conflict would resemble World War II in scope and that containment and deterrence were better options. In the 1960s, the Kennedy administration feared that Chinese leader Mao Zedong was mentally unstable and proposed a joint strike against the nascent Chinese nuclear program to the Soviets. (Moscow rejected the