What a dud would mean

Speculation is growing in some quarters that North Korea's big bang wasn't nuclear after all. If that view gets further support from experts, we may start to hear arguments that a strategic window of opportunity has opened. North Korea, the reasoning might go, has simultaneously demonstrated dangerous political recklessness and military incompetence. In effect, they've called their own nuclear bluff. Some reputable folks were advocating military strikes well before the test, and they may seize on the latest developments to reissue the call.

We should be wary. The fundamental strategic and moral problem with military action against North Korea is not their nuclear arsenal—it's their ability to wreak havoc on the south through conventional weapons. In this sense, the nuclear test—successful or not—has not changed the strategic picture on the peninsula dramatically. What it has done, one hopes, is create the political unanimity required to take the steps we should have already taken: namely, enhancing scrutiny of ships leaving North Korea to prevent any leakage of their fissile material and missile technology and bolstering regional missile defenses.