HARBIN, China — The Sino-American meeting was droning on about economic development in this northeastern corner of China when a Chinese scholar suddenly injected a pointed question that, in effect, accused the United States of encouraging Japan once again to become an aggressive military power.

The scholar at the Heilongjiang Academy of Social Sciences, Wang Xiliang, launched into a tirade asserting that Japan, with American approval, had shed its postwar pacifist stance to resume its aggressive posture of 1931-1945. Referring to the recent deployment of Japanese forces to Iraq, Wang contended: "Japan should not send troops outside of Japan."

Wang's outburst was directed at the commander of U.S. forces in Asia and the Pacific, Adm. William Fallon, who listened intently, then replied: "We welcome Japan's engagement in peacekeeping operations." He said the Japanese "are trying to do things that are helpful, and they are not trying to do anything that is militarily aggressive."

Fallon told the Chinese, who often berate the Japanese for their brutal 15-year occupation of China, that he was more interested in the future than in the past. He told Wang and the dozen Chinese scholars and military officers around a table: "It's not helpful to keep pointing to history."

The admiral, on his third visit to China in the past year, was in Harbin recently to expand contacts with the Chinese, particularly the People's Liberation Army. The U.S. has been trying to persuade the Chinese that American intentions are peaceful while exposing them to U.S. military capabilities to avert a possible miscalculation.

Fallon was successful in at least one respect, making fresh contacts. Maj. Gen. Kou Tie, China's military commander in this region, told Fallon just before hosting a banquet that he was the first American he had ever met.

Wang's bitter condemnation of Japan reflected a downward spiral in Chinese-Japanese relations over the last five years. To assess those relations, the Center for Naval Analysis, National Defense University and Institute for Defense Analyses, all Washington think tanks, have joined with the Pacific Forum of Honolulu in a six-month study.

The 30 political scientists, economists, retired military officers, government officials, and diplomats who have taken part agreed that the deterioration does not serve U.S. interests. They noted that Washington has been seeking improved relations with China at the same time it has been pursuing a stronger alliance with Japan.

Beyond that, however, there was no unanimity on the causes of the slide, or what should be done about it — except for treading carefully. To encourage candor, conference rules preclude identifying the participants.

Some specialists asserted that China and Japan are caught up in a rivalry for leadership in Asia. A preliminary conference report said others argued that "competition for leadership is more a symptom than a cause of tensions." Still others suggested that the competition came from China as "Japan is not much interested in leadership."

In Tokyo in May, several Japanese said much the same in interviews. They summed up their nation's ambitions as continued prosperity, security in alliance with the U.S., political recognition as a permanent member of the United Nations Security Council, and "not to be bullied by China."

In economics, another conference report said, "experts were split on whether there is a genuine rivalry between China and Japan for economic dominance in Asia." It continued: "Economic data suggest that a rivalry does not exist, given that the Chinese and Japanese economies are complementary, not competitive."

Militarily, Japan is no match for China; thus Japan's need for alliance with the U.S. Japan has 239,000 people under arms, China 2.3 million. China has nuclear weapons, long-range bombers and is building a blue- water navy. Japan has no nuclear weapons, no long-range bombers and a modest blue-water navy. China spends $90 billion a year for military forces, twice what Japan spends.

For Washington, a report said, "the forces of nationalism and domestic politics in both countries make this situation particularly resistant to third- party intervention." Even so, the U.S. is involved because, the report said, territorial claims in the East China Sea "could lead to war." The U.S., with its security treaty with Japan, could be dragged in.

"The U.S. has to be clear about policy objectives," a report concluded. Given the Bush administration's preoccupation with Iraq, a war on terror, the clash between Israel and Hezbollah, and worries about the economy — not to say the mid-term elections in November — asking for clarity elsewhere may be only wishful thinking.

Richard Halloran is a Honolulu-based journalist and former New York Times correspondent in Asia. His column appears weekly in Sunday's Focus section.