Now that North Korea has announced its withdrawal from the Nuclear Nonproliferation Treaty, the International Atomic Energy Agency is obliged to report Pyongyang's noncompliance to the United Nations Security Council. In turn, the Security Council will be hard pressed to avoid tabling a tough economic-sanctions resolution.

In the Bush administration, attention is focusing on whether China can, or will, help solve the crisis. Early indications are not encouraging. On Friday, U.S. President George W. Bush telephoned Chinese President Jiang Zemin seeking support. While the White House spokesman put a positive spin on the conversation, saying "the two presidents agreed to continue to work together to help ensure the peace and stability of the Korean Peninsula," the Chinese version wasn't as accommodating. According to the Chinese foreign ministry, President Jiang simply insisted that, "dialogue is the most effective path."

Mr. Jiang even lamely tried to explain that he had no idea what the North Korean leader, Kim Jong Il, was up to. After the phone call, exasperated White House officials privately derided Jiang's attitude as "free-rider syndrome."

What Mr. Jiang's means by "dialogue" is, of course, direct negotiations between Washington and Pyongyang. Rather than seeing North Korea's nuclear brinkmanship as a challenge to the entire international nonproliferation structure, China fully supports North Korea's strategy of turning the crisis into a bilateral dispute with the U.S.

Beijing's only public reaction to Friday's announcement was a mild expression of "concern," in contrast to the criticism that emanated from Russia, Japan, South Korea and, most significantly, France.

Speaking during a visit to China, French Foreign Minister Dominique de Villepin warned that North Korea's action is "heavy with consequences that must be dealt with by the United Nations Security Council" and "underscores the necessity and the urgency of international mobilization." The significance of his comments lies in the fact that France holds the presidency of the United Nations Security Council in January and so is in a position to influence the likely next step -- U.N. economic sanctions against North Korea.

The sanctions clock could start ticking immediately. IAEA Director-General Mohamed El Baradei is ready to submit his agency's report to the Security Council. Some in the Bush administration expect that to be swiftly followed by a draft sanctions resolution: not from the U.S. (as that would only play into Pyongyang's hands), but from one of the other permanent members of the Security Council, most likely France.

By raising the ante with its NPT withdrawal, Pyongyang invites the Security Council to forego the nicety of an initial "warning" resolution and move directly to a tough sanctions resolution under Chapter VII of the U.N. Charter. Chapter VII is reserved for "threats to the peace, breaches of the peace and acts of aggression," and would allow sanctions to be imposed immediately.

In June 1994, then U.S. President Bill Clinton drew up plans for a two-stage sanctions regime against North Korea under Chapter VII, before abandoning this in favor of striking the Agreed Framework with Pyongyang. Had these been implemented, the first phase would have banned the flow of money from North Koreans living abroad to their families back home, stopped all military shipments in and out of North Korea and terminated North Korea's reliance on the U.N. for economic and nuclear cooperation. The second phase would have been a full trade embargo.

Japan offered its own three-stage plan: a warning resolution, then sanctions on arms sales and technical cooperation and finally a ban on financial remittances. Without oil, hard currency, even imports of food, the general expectation was that North Korea's economy would quickly collapse, and the overthrow of the regime seemed sure to follow.

If the present crisis escalates, and especially if intelligence indicates Pyongyang might put fissile cores up for sale on the international black market, any new U.N. sanctions resolution will have to go further and include a naval and air quarantine of North Korea. Indeed, U.S. Secretary of State Colin Powell has already warned that the sale of nuclear weapons would cross a "red line."

Tomorrow, U.S. Assistant Secretary of State for East Asia James Kelly will arrive in Beijing, to brief China on the latest developments and probe whether they will support sanctions against Pyongyang. On Sunday, Assistant Secretary of State for Arms Control and International Security John Bolton will follow in his footsteps through Beijing -- this time to remind the Chinese that the U.S. still expects them to cease their own weapons proliferation activities. Washington sees China's continuing sale of chemical weapons material and missile components to rogue nations as evidence that China remains more part of the problem than the solution.

The Bush administration is divided over how to handle Beijing, when it comes to North Korea. Some in the State Department's East Asia and Pacific Affairs Bureau, which is headed by Mr. Kelly, believe self interest may be enough to persuade China to help restrain Pyongyang, for fear that a nuclear North would push Japan to militarize. But they also recognize that Beijing may use the crisis as leverage with Washington over both Taiwan and its own proliferation activities -- and are inclined to make concessions on both issues, if necessary.

Others in the administration say it would be wrong to offer China anything in return for helping with North Korea. They argue that for 50 years the U.S. kept the nuclear lid on Asia, stamping out nascent weapons programs in South Korea and Taiwan. In the 1970s and 1980s, for example, IAEA inspectors and U.S. intelligence detected two separate Taiwanese plutonium bomb projects. In both cases, Washington used its economic and military support to force the government in Taipei to terminate them. The U.S. did not do this as a favor to China but in recognition that nuclear proliferation is an element of instability in a crisis-riven region. They say that is now China's turn to act with similar maturity.

All the signs so far suggest this is unlikely. China could, of course, derail any sanctions by wielding its veto in the Security Council. But Beijing would face a dilemma in doing so. By obstructing the U.N., they would be seen as Kim's "nuclear enabler." This would stampede Japan into a joint missile defense with the U.S. -- and worse. There is already talk in Washington about rethinking American opposition to Japan's nuclear option.

If it allows U.N. sanctions to go ahead and abides by them, China would be obliged to seal its borders with North Korea. This too would be a nightmare for Beijing. China is Pyongyang's last lifeline of oil and food, and to constrict that lifeline would cause chaos in North Korea.

By supporting sanctions, China might further destabilize the dirt-poor North Korean nuclear dictatorship and risk a sudden influx of refugees into its sensitive border areas. Yet, by propping up Kim Jong Il, they prolong the agony. The collapse of the Pyongyang regime would mean that China would either have to replace it with a pro-Beijing puppet government or welcome the emergence of a unified democratic Korea under Seoul. Beijing, which still considers itself socialist, cannot bring itself to abandon its little Stalinist brother.

Hard decisions cause paralysis in Beijing, and this is exacerbated by the modest leadership transition now underway there. Chinese leaders frequently tell visiting Americans they have no power over Kim Jong Il. The truth is, they have the power to bring him down. They just don't want to use it.

Mr. Tkacik, a research fellow at the Heritage Foundation in Washington, D.C., served in the U.S. foreign service in Beijing, Guangzhou, Hong Kong and Taipei.