A Nuclear Nightmare Comes True

North Korea, defying urgent pleas and intense pressure from the rest of the world, successfully tested a nuclear bomb this morning at a site near the city of Kilju in country's northeast, about 400km from the capital Pyongyang. The test moves the issue of Pyongyang's nuclear capability into a tense new phase. For more than a decade, the United States and North Korea's neighbors in east Asia—South Korea, Japan China and Russia—have worked to get Pyongyang to abandon its nuclear ambitions. Those efforts have proved fruitless, and indeed the timing of the North's test today seemed particularly pointed. On Sunday,...