PYONGYANG is again at the center of an international crisis. As a retaliation to the UN Security Council's presidential statement issued on Monday condemning North Korea's April 5 rocket launch, demanding an end to further launches, and calling for expanded sanctions, Pyongyang threatened to boycott the six-party talks and give up disarmament agreements, recover disabled nuclear facilities, resume plutonium production, and take all measures to increase its nuclear deterrence. Once again, Pyongyang is playing the tit-for-tat strategy to prepare for a larger bargaining chip in a new round of nuclear negotiation.

Tokyo and Washington are pushing for tighter sanctions. Beijing, by contrast, is urging caution. China is concerned that more pressure or sanctions would run counter to...