A New Nuclear World

North Korea's nuclear weapons test creates serious problems for the U.S. and its allies in trying to rein in the rogue state—and opens a dangerous new chapter in nuclear proliferation.

At roughly 10:30 Monday morning Pyongyang time, the number of card carrying members of a once exclusive club—those countries armed with nuclear weapons—increased yet again. In a mountainous region 385 km northeast of the North Korean capital, Kim Jong Il's government showed that it was as good as its word when it comes to saber-rattling. After warning last week that it intended to test a nuclear weapon, it did—defying the international community and daring it to do something in response.