The initial reaction to the North Korean nuclear breakout is to focus almost exclusively on the unpalatable choices available to the Bush administration. That is a shortsighted response. This is a crisis for the world's five declared nuclear powers and for their responsibilities as the senior partners on the U.N. Security Council. They must meet it together or watch their world change in fundamental, extremely dangerous ways.

North Korea's determination to build a nuclear arsenal has been equally impervious to the carrots of Bill Clinton and the verbal sticks of George W. Bush. The aura of invulnerability conveyed by a dozen or so nuclear warheads is for Kim Jong Il a greater asset than anything any American president can grant. Atomic warheads are intended to make the Korean dictator -- or Saddam Hussein or Iran's ruling ayatollahs -- politically immortal.

North Korea's challenge in this instance is not just to Bush's rhetoric or to the U.S. military presence on the Korean peninsula. This is a challenge to the increasingly unsteady global nuclear balance and the architecture of treaties, national policies and a system of incentives and sanctions that has for more than three decades sought to restrict the flow of nuclear weapons technology.

The great powers must now move in concert -- preferably through the Security Council -- to turn from a failed strategy of nonproliferation to joint concrete measures to deal with the consequences of proliferation. The alternative will be for every nation that has the resources to pursue its own mix of missile defense, preemptive military strategy and a nuclear arsenal of its own. The alternative, in other words, is the law of the nuclear jungle.

This is not to absolve the Bush administration of having to play the leading role in fashioning a response to the crisis, or of its blunder in challenging the North Koreans in October over Pyongyang's covert nuclear weapons program without having a strategy in place to deal with it.

But the administration has taken the right approach since October in stressing the international and long-term repercussions of North Korea's breakout from the 1994 Agreed Framework. A tactical "concession" by Bush in the form of agreeing to formal negotiations with North Korea while Pyongyang continues to break its previous agreements neither could nor should settle this face-off. Unilateral U.S. economic sanctions are likely at this point to be ineffective and diplomatically damaging to U.S. interests.

"We are looking for ways to communicate with the North Koreans so some sense can prevail," Secretary of State Colin Powell said recently. He's right. And that communication should come from the Security Council, in a resolution demanding that North Korea resume cooperation with international inspections and other restraints or face global sanctions.

When Washington let a North Korean shipment of missiles go ahead to Yemen last month, U.S. officials bemoaned the lack of legal international instruments to halt such weapons deals, which earn North Korea an estimated 40 percent to 50 percent of its total export revenue. The administration should pursue this chance to acquire some new, meaningful tools.

The Security Council could offer Pyongyang nonaggression assurances and economic aid in return for a verifiable halt to its nuclear programs. At the same time, the U.N. body should threaten a global ban on North Korean arms shipments if defiance continues. The United States would be essential, but not alone and exposed, in either approach.

Americans and their allies, friends and foes abroad need to understand the stakes here, which far exceed the deep irony of the "unilateralist" Bush team's turning to the United Nations first on Iraq and now perhaps on North Korea. This is global politics played at the ultimate level.

Bush is pushing to the limits an international system and ethos that he doubts can protect U.S. interests sufficiently. He is asking the United Nations to take on greater responsibilities, not because he thinks he has no acceptable alternative but because he believes he does have one, as a last resort. That alternative is a 21st century version of Fortress America that will do what it must to survive in a post-9/11 jungle. Bush's continuing and incessant emphasis on missile defense is the clearest window on this self-protective impulse.

Those in South Korea who mistakenly hold the United States responsible for this crisis and want U.S. troops out of their country may be posing a question that Saudis, Germans and the rest of the world now also face: Are we safer with more America or less America in global security matters? They should remember the dangers of answered prayers. This is an administration prepared to take less as an answer.