Reports that North Korea might soon test a nuclear weapon have prompted a flurry of diplomatic activity in north Asia. The United States and others are calling on China to do more to persuade its longtime communist allies in Pyongyang to return to disarmament negotiations. Political analysts say a nuclear test could actually help that process, because it might provoke China enough to take stronger measures against its neighbor.
A North Korean waitress serves tea to customers at a busy restaurant in Beijing, one of several that China allows the North Korean government to run in the city.
The restaurant is an example of the soft power that China uses to nudge North Korea to carry out economic reforms like the ones Beijing began 30 years ago.
The waitress says business is good, and proudly adds that customers enjoy dishes made with ingredients brought all the way from Pyongyang.
But these ventures have done little to sway North Korea into behaving the way China, Pyongyang's historic ally, thinks it should. North Korea's missiles tests in July are one example of China's limited influence.
China, until recently reluctant to criticize the North, joined other members of the U.N. Security Council in approving a resolution that condemned Pyongyang, and effectively imposed sanctions on North Korea.
Still, Beijing is eager to maintain good ties with its old ally, and is Pyongyang's chief supplier of food and fuel. Shi Yinhong is an expert on international relations at the People's University in Beijing.
"If North Korea conducts a nuclear test, it would push China into a very difficult dilemma," he said. "On the one hand, China would have to impose more pressure on North Korea. But on the other, China would worry that its relations would be severely damaged, or that, even worse, there would be an internal collapse in North Korea."
Chinese officials have privately said they fear that a collapse of the Stalinist North Korean regime could be even more serious for China than a nuclear test. A crisis in the North could send a flood of refugees into China, and could lead to violence on the border. It also could mean the loss of one of Beijing's few remaining communist allies.
The North carried out its missile tests, despite Beijing's warnings to avoid causing regional tensions. Now, Pyongyang may be preparing a nuclear test, also against Beijing's wishes.
Some regional political analysts think that, if the North conducts a nuclear test, Beijing would quickly re-evaluate its relationship with Pyongyang.
Peter Beck is a northeast Asia expert in Seoul for the International Crisis Group, a European research organization.
"The more provocatively the North behaves, the more it threatens stability in the region by pushing Japan closer to the United States, or encouraging Japan and other countries in the region to beef up their military capabilities, and that's not in China's interests," noted Beck. "The North has been a buffer zone, and, in the last several years, the Chinese have viewed North Korea as a target of economic development and investment. But, again, the more provocatively the North behaves, the more that lowers the value of North Korea to China."
One element for China to consider is its relationship with the United States, which leads the effort to get North Korea to give up its nuclear weapons programs.
In a 1961 treaty, China pledged to defend the North. However, there are indications that China might not stick to that commitment. Chinese Foreign Ministry spokesman Qin Gang recently suggested China will do everything possible to avoid a confrontation with the United States or anyone else over North Korea.
"We will work with North Korea to promote the development of neighborly and friendly relations in the spirit of this treaty, to maintain peace and stability on the Korean Peninsula, which is the cornerstone of China's policy on North Korea. China is willing to make joint efforts with other nations to achieve this goal," he commented.
If the North goes ahead with a test, it is likely to conduct an underground nuclear explosion. Daniel Pinkston, head of the East Asia Nonproliferation Program at the Monterey Institute of International Studies in California, says North Korea has not shown that it could conduct a test using missiles, pointing out that at least one of the rockets Pyongyang tested in July failed.
"That's a more difficult engineering feat than just making a large redundant system that you could put on the back of a flatbed truck, for example, and just detonate it. So, I think they probably have something that they're confident could work, and they could put it in a tunnel and detonate it for political reasons, if they needed to do that," said Pinkston.
North Korea has said it wants a nuclear arsenal, so it can defend itself from what Pyongyang says is an impending U.S. attack. Washington says it has no plans to strike North Korea.
Three years of six-nation negotiations have made no progress getting North Korea to give up its nuclear programs.
Many diplomats say the talks have stalled, largely because the five negotiating partners have no common strategy toward North Korea. China, for one, has stuck by its soft approach over tougher measures the U.S. and Japan have advocated.
But analysts say China is drawing closer to a moment of truth, when it must decide between supporting a troublesome ally, or aligning itself more closely with the U.S. and Japan. While China has historically viewed those countries as enemies, it now has large trade and strategic interests with them.
The experts say that, while a North Korean nuclear test might be initially destabilizing, it may, in the long-term, bring nations together to pressure North Korea to either change its policy, or change its leadership.