North Korea's announcement this week of plans to test a nuclear weapon is hardly surprising. The six-party talks to negotiate an end to its nuclear program are dead, and the North faces escalating financial and economic sanctions by the United States and its allies.

Experts have long debated the real motivations of the North in developing nuclear weapons. Some contend that the nuclear program, even the latest pronouncement, is simply a bargaining chip to gain security guarantees and economic aid. Others see a long determination to become a nuclear state.

The North Korean leaders may have begun the nuclear program as leverage. But the U.S. invasion of Iraq seems to have hardened their conviction that the only way to protect their nation and their regime is to join the nuclear club. The North Koreans want to become a Pakistan rather than an Iraq.

Still, officials in Pyongyang hesitated to cross the provocative line of visibly demonstrating their capability. Pressure is being mounted to get them to back down from their pledge. But for a variety of reasons, they apparently believe the timing for a test is now optimal.

First of all, they hope to blame the Bush administration for their decision. In the statement issued this week, the North Korean government argued that alleged American war plans justify a nuclear test, a position that reflects the views of the North Korean military.

Second, the North anticipates the test will be successful. Although a plutonium weapon is more complicated than a uranium bomb, it is quite likely that the North now has sufficient confidence in a Nagasaki-style primitive bomb. This success would be an object of pride for an otherwise failing state, and bolster its claim to the status of a world-class military power.

Third, the North Koreans see their potential enemies tied down and unable to respond effectively. The Bush administration is locked into a disastrous war in Iraq, and about to be weakened even more if the Republicans lose the upcoming midterm elections. In South Korea, the government of President Roh Moo Hyun is already a lame duck and politically paralyzed.

Fourth, Pyongyang may bet that China and South Korea, the two principal sources of trade and economic aid, would not join the United States and Japan in any real sanctions against the North. The July missile tests by North Korea provoked international uproar and led to a U.N. resolution. But the real impact has been minimal.

Finally, the North may calculate that testing will facilitate Japan's efforts to become a "normal'' nation with a broader military role in the region. That prospect could increase tensions in Northeast Asia, especially between Japan and China, and that, the North may believe, is not necessarily bad for it.

The United States, South Korea and China must act together to show that these calculations are misguided and that the North will pay a painful price if it goes ahead. Certainly this severely tests the troubled American alliance with South Korea and the emergent partnership with China. But Pyongyang's miscalculations also offer an opportunity to repair the strained alliance and create a new structure of security cooperation in Northeast Asia.

It is no secret that Seoul and Washington have been at odds over how to deal with North Korea. But the test announcement has already accelerated a shift in South Korean opinion. Rather than holding the United States responsible for the current impasse, most Koreans now see North Korea as the instigator of crisis.

South Korean officials understand that without reinforcing the alliance now, no policy toward the North can be effective. The United States and South Korea should urgently agree on common action plans -- including a shutdown of investment and economic assistance from the South to the North -- and make those consequences clear to Pyongyang.

The planned visits of newly installed Japanese Prime Minister Shinzo Abe to Beijing and Seoul next week offer a similar opening to turn threat into opportunity. Abe intends to repair tattered ties to those Asian neighbors. Now the three Northeast Asian powers can demonstrate that a nuclear test will not lead to increased tensions but to the complete isolation of the North.

The danger of escalating actions that could lead, again, to war on the Korean peninsula is grave. The North Koreans should be assured that the door to a diplomatic solution remains open to them. But they must also understand that by profoundly misreading this moment, the North Korean leadership now stands completely alone in Northeast Asia.

Reprinted by permission.

Given Tehran's defiant response to the European and American effort to constrain its nuclear program, it is time for bolder diplomacy out of Washington. U.S. President George W. Bush should take a page from the playbook of Ronald Reagan, who negotiated with an evil Soviet regime--competing in the war of ideas, but addressing the enemy's security concerns through arms-control agreements.

Iran's intransigence is both deeply unfortunate and perfectly predictable. It is unfortunate because Tehran's refusal to suspend its uranium-enrichment operations immediately--as demanded in July by the U.N. Security Council in a legally binding resolution--suggests that Iran is moving more quickly than expected toward a nuclear-weapons capability. Tehran has now turned the nuclear crisis into a test of the whole U.N. Security Council system. And Russia and China's current position, threatening to veto any biting sanctions against Iran, suggests that the Security Council may well fail this crucial test.

Tehran's response is predictable, however, because the offer on the table contains both inadequate economic carrots and barely credible threats of sanctions and military force. The carrots appeared impressive at first glance--in return for a suspension of enrichment we reportedly promised to provide light-water nuclear reactors and to help Iran with civil aviation and telecommunications technology. But we did not offer the one incentive that might possibly work, security guarantees that could reduce Iran's desire for nuclear weapons.

This omission is striking. The Iranian government can't talk openly about their security concerns because that would blow their cover story that the nuclear program is only for energy production. And Washington does not want to discuss such worries because it wants to keep open the possibility of removing the regime by force. "Security assurances are not on the table," U.S. Secretary of State Condoleezza Rice too cleverly argued this spring: "It is a little strange to talk about security guarantees ... I thought the Iranian position was that they weren't developing a nuclear bomb."

This is partly a crisis of our own making, as the Bush administration has practiced the reverse of Teddy Roosevelt's maxim--speaking loudly and carrying a small stick. Think about how Tehran reacted when Bush stated (in his second Inaugural Address), "The rulers of outlaw regimes can know that we still believe as Abraham Lincoln did: 'Those who deny freedoms to others deserve it not for themselves; and, under the rule of a just God, cannot long retain it." Or when Bush dramatically told reporters last April that "all options are on the table," in direct response to a question about whether he was considering a nuclear attack against Iran. Such statements only encourage Iran to develop a nuclear deterrent quickly, before the United States can carry out its perceived aggressive intent. Last month, Iran's National Security Council Secretary Ali Larijani pointedly complained about such rhetoric. "How can a side that wants to topple the regime also attempt to negotiate?"

Given the current vulnerability of U.S. forces in Iraq, the deteriorating situation in Afghanistan, and the lack of Israeli success against Hizbullah, Iranian officials seem confident that they face no immediate threat of a U.S. military assault. But they are clearly worried that Bush just might attack Iran right before he leaves office in January 2009, or that his successor might do so once U.S. forces withdraw from Iraq.

The best way to prevent a nuclear Iran is for Washington to offer the kind of security assurances that might reduce support in Tehran for building a nuclear arsenal. It will be hard to make such assurances credible, but a public U.S. promise to take forcible regime change off the table, and a U.N. Security Council commitment to protect the "political sovereignty" of Iran could help. Involving the Security Council could also pull China and Russia back into the nonproliferation coalition and enhance the U.N.'s legitimacy.

There is very little time left, which means negotiations should begin despite Iran's unfortunate opening position. Tehran's response reportedly indicated a willingness to negotiate all aspects of its nuclear program, so working out an agreement for Iran to limit itself to low-level uranium enrichment might still be possible. This would work only if Tehran accepts full IAEA inspections and a freeze on future centrifuge construction. Will they? The one thing that might cause Tehran to do so, and that would compensate for any loss of face, would be an assurance that the United States will not launch another preventive war, as it did in Iraq, to remove the Iranian regime. If in turn we get a nuclear-free Iran, that's a good deal for the West as well.