For the past year China has led the quest for a negotiated solution to the Korean nuclear crisis. It facilitated and hosted three-way talks with the United States and North Korea a year ago this week and two sessions of the six-party talks (adding South Korea, Japan and Russia) in August and February. Its officials crisscrossed the globe to explore potential areas of common interest and compromise and this week hosted North Korean leader Kim Jong Il to explore options for the beleaguered Korean Peninsula. Yet, in each of the formal talks, the Chinese have been discouraged by the minimal results. They are now questioning U.S. intentions toward Korea and, in the longer term, toward China.

Beijing considers the unchecked expansion of North Korea's nuclear weapons to be a real possibility, and its reasoning starts with the record of U.S. policies toward nuclear proliferation. That record, the Chinese argue, is mixed and often contradictory. As a result, China worries that Washington might continue to tolerate the program so long as Pyongyang did not cross key red lines, such as the transfer of nuclear materials to terrorists.

Whatever Beijing's past position on nuclear matters, many senior Chinese now regard nuclear weapons on their border to be a direct threat to their national security and suspect Washington of downplaying that danger. For them, it is no great leap to the conclusion that the unfettered growth of the Korean program might embolden others in Asia, including Taiwan, to acquire nuclear weapons despite verbal opposition from Washington. Beijing's leaders can easily imagine how that nightmarish turn of events would undermine the nation's drive toward modernization and end strategic cooperation with the United States.

Despite the fact that all parties at the six-party meeting in February endorsed the dismantling of the North's nuclear weapons program, the Chinese fear that the talks may be dead in the water. Following that meeting, they began to debate other ways to resolve the crisis. They had already reorganized the leadership team responsible for North Korean affairs, and that team had begun acting to prevent the worst case, including offering further inducements to Kim Jong Il this week. Whereas last fall the talk of deepening U.S.-China cooperation on Korea pervaded the news, now, especially after Vice President Dick Cheney's uncompromising stand on Korea and Taiwan last week, the reverse is occurring.

What China can do in these circumstances is quite limited. Its influence on North Korea is largely determined by what the United States does or doesn't do. By refusing to negotiate on a staged process leading to the eventual dismantlement of Pyongyang's nuclear weapons, Washington has tacitly allowed the North's program to proceed. It has rejected proposals for a temporary freeze, technical talks and any interim steps short of the unconditional and complete ending of the program. The result is virtual paralysis.

Beijing has been able to work with North Korea only when it could find areas of potential compromise between Washington and Pyongyang. It cannot or will not act alone to exert pressure because this would jeopardize its influence on the North. Contrary to a widely circulated story, Beijing did not cut off energy shipments to North Korea for three days in 2003. Beijing would not take such a counterproductive action when its main influence with the North lies in the kind of quiet diplomacy being practiced this week with Kim Jong Il.

Many in Beijing are beginning to question whether there might be a more promising approach with Pyongyang. Should the Chinese, South Koreans and Russians conclude that making progress toward the common goal of the North's complete nuclear disarmament is out of reach, for example, they reluctantly might translate their joint offer of aid in February into a quid pro quo for a partial agreement, such as a limited freeze, that would allow the situation to stabilize. China could worry that such an independent action could endanger the common front with Washington. At the same time, it could calculate that the United States would be sufficiently pleased with any solution that halted the North Korean nuclear program.

None of these developments may come to pass, of course, but who could have imagined a year ago that Washington would have permitted the situation to deteriorate to the present point?

History shows that these sorts of trade problems can last a long time. In the '80s, Japanese and U.S. semiconductor manufacturers sparred constantly. A truce only began in the '90s when Japan was already mired in an economic slide. Moreover, such trade quarrels can lead to global incompatibilities that linger for years and hurt both importers and exporters. "I believe there are genuine security concerns on China's part, although the domestic industry is also likely to benefit," said Lawrence Lau, the Kwoh-Ting Li professor of economic development at Stanford University. "This happens quite often. Our cell phones do not work in Japan, so the Japanese manufacturers and distributors have a lock in their home market. However, that did not exactly help Japan. By setting a different standard, Japan has actually limited the growth of its own cell phone companies."

ECONOMIC, POLITICAL TIES DISPLACING RIVALRY China's government has sentenced two of its citizens to life in prison for their role in securing prostitutes for hundreds of male Japanese visitors in the southern city of Zhuhai last autumn. The Chinese government is also pressuring Tokyo to turn over the Japanese businessmen who allegedly requested the prostitutes. This story made headlines around the world, and fits well with how the world press typically covers Sino-Japanese relations. Regrettably, such incidents recur with enough regularity to feed the media machine that continues to stir a nationalism rooted in conflicting historical memories. Japanese Prime Minister Junichiro Koizumi's annual visits to the Yasukuni Shrine -- which is widely viewed as a symbol of Japan's former militarism -- is a conspicuous example of this. The publicity that the press gives to these visits has helped impede an invitation to Koizumi from China's leaders for a state visit. Recently, the discovery of mustard gas canisters left behind by Japanese forces during World War II has also served to keep memories of the Imperial Japanese Army's wartime conduct alive among older Chinese. Moreover, rival Sino-Japanese claims to the Senkaku (or Diao Yutai) Islands resurfaced last year when the Japanese government leased three islets in the chain from private parties. The action, purportedly undertaken to reduce the prospect of landings and demonstrations by Japanese right-wingers, set off a brief, though frenzied, reaction in China, as well as in Hong Kong and Taiwan. Meanwhile, differences over Taiwan also foster tensions periodically, such as when former Taiwanese President Lee Teng-hui sought to visit Japan for medical treatment. But this is not the whole story. Although such incidents reveal a troubling level of mistrust between the Chinese and Japanese that is not merely a product of media coverage, it is noteworthy that both governments have worked consistently, diligently, and with considerable success to resolve such problems and contain their political fallout. Of course, official relations between the two countries are marked by much political and economic competition -- some of it healthy, some of it a possible harbinger of future strategic rivalry. The competitive strain in Sino-Japanese relations is especially visible in energy politics. Demand for oil in Asia is growing rapidly, and with China and Japan increasingly dependent upon imports, each has naturally sought to improve its energy security by diversifying sources of supply. Both countries covet access to Russian reserves, especially those located in the Angarsk fields of Siberia. Last spring, China appeared to have locked up a Russian commitment to build a pipeline to service the China market at Daqing. Japan, however, raised the ante with new offers of financial incentives. Its bid for an alternative pipeline to Nakhodka to serve Japanese, Korean and other markets remains alive, creating another point of competitive friction. In their rivalry for leadership in promoting Asian regional cooperation, meanwhile, China has taken an early lead. Nearly two years ago, China trumped Japan by offering a Free Trade Agreement to the members of the Association of Southeast Asian Nations, while front-loading its own tariff concessions. But this backdrop of contention and competition masks emerging collaborative aspects of Sino-Japanese relations that are profoundly important. For example, trade and investment flows continue to expand rapidly. Bilateral trade topped $100 billion in 2003, as Japan's exports to China increased by more than 10 percent, fueled by semiconductors, electrical equipment and automobiles. Meanwhile, China replaced the United States as Japan's biggest source of imports, and is now one of the few non-members of the Organization of Petroleum Exporting Countries with which Japan runs a trade deficit. Similarly, direct investment by Japanese firms is increasing as they relocate production facilities to China to capitalize on lower labor costs and high-quality engineering talent. Of course, there is no assurance that today's expanded commerce will preclude eventual strategic rivalry, or succeed in erasing lingering wartime animosity. But both countries now place a premium on extending their economic interdependence. Ultimately, the historical wounds that have long divided China and Japan, and the more current diplomatic flash points that the global media inevitably trumpet, tell only part of the Sino-Japanese story. There are economic and geopolitical rivalries between China and Japan that dwarf in importance the high-profile insults to national pride that make headlines. But there are also compelling economic and political inducements toward cooperation that prevent these rivalries from developing into full-blown crises. MICHAEL ARMACOST is a former U.S. ambassador to Japan and is a distinguished fellow at the Asia/Pacific Research Center of Stanford University. He wrote this article for Project Syndicate.