In Tokyo many years ago, an Australian intelligence officer undercover as a business executive was asked what was his nation's fundamental interest in Japan.

In a flash, he blurted out: "To keep Japan onside."

That was in the middle of the Cold War between the United States and the Soviet Union. The Australian's mission was to help prevent Japan, which then harbored a strong Marxist left wing, from slipping into the orbit of the Soviet Union.

Today, Australia and the United States are engaged in a similar task of keeping Japan "onside" even though relations among Tokyo, Canberra and Washington seem sound.

Prime Minister John Howard of Australia and Prime Minister Shinzo Abe of Japan agreed last week to begin negotiating a new trade pact. The United States and Japan are working out details of a realignment of U.S. forces in Japan.

Secretary of State Condoleezza Rice and Deputy Secretary of Defense Gordon England met in Washington last week with Foreign Minister Alexander Downer and Defense Minister Brendan Nelson of Australia to discuss, among other things, U.S.-Australia-Japan security cooperation.

It is the long run that concerns Australian and American diplomats. The two nations are intent on encouraging the Japanese to continue shucking the pacifist cocoon into which they retreated after the devastating defeat of World War II and to be more active internationally.

At the same time, America and Australia are eager to keep Japan from slipping under the influence of China.

And Americans and Australians who are students of Japan have noted the revival of a nationalist streak in Japan, the consequences of which are unpredictable.

Japan is not a volatile nation; indeed, most changes come slowly. The Japanese, however, have long felt isolated from the rest of the world.

The president of Japan's Defense Academy, which educates officers of all services, wrote last week that Japan had become "sulky and angry, driven by self-respect and exclusive nationalism." Makoto Iokibe noted that his nation had "reacted keenly to anti-Japan campaigns in China and South Korea."

Australians and Americans have thus sought to reassure the Japanese that they are valued allies. In some respects, Australians share Japanese anxieties. Australia is culturally, politically and economically a Western nation of 21 million people. Geographically, however, it is situated next to an Asia where it lacks major allies and therefore looks to the U.S. as its main protector.

Chinese diplomats have looked askance at the emerging three-way alliance and complained that it is part of a U.S. conspiracy to "contain" China. All three deny it, an Australian diplomat saying: "This has nothing to do with China. This is all about Japan."

A trilateral dialogue among Australian, Japanese and U.S. senior officials started in 2002. Then began a "track two," or unofficial, dialogue among Japanese, Australian and American scholars, security specialists and former officials. They met, for instance, at the Asia Pacific Center for Security Studies, the educational and research center in Honolulu, in 2004.

Last March, Secretary of State Rice, Japan's foreign minister, Taro Aso, and Foreign Minister Downer met in Sydney to raise the dialogue to ministerial level. Beyond discussions of China's rising power, North Korea's nuclear threat and Burma's jailing of political prisoners, were talks about responding to the potential influenza pandemic in Asia. A second meeting is to be held in early 2007 in the U.S.

On the long-term question of Japan's isolation, Asia Pacific Center scholar John Miller has written that Japan has long been an "outlier," a nation "in" but not "of" Asia. In pre-modern times, Japan refused to pay tribute to China, unlike Korea and Vietnam, and went into seclusion. Since then, Miller wrote, Japan has "oscillated" between Asia and the West.

In the late 19th century, Japan became a Western-style industrial and military power, and carved out an Asian empire in which Japan sought to drive Western powers from Asia. That led, in 1945, to Japan's catastrophic defeat and occupation.

In the postwar era, Japan again embraced the West, reinvented itself as a democracy, and succeeded in becoming an economic powerhouse. At the end of the Cold War, Miller wrote, Japan seemed ready to reject the West again in favor of seeking the leadership of Asia. Instead, Japan tilted toward the U.S.

Miller concluded: "It is as yet unclear where the Japanese will find a balance among an Asian role, the American alliance, and a 'normal' international political role." That assessment seems to motivate Americans and Australians who want to keep Japan onside.

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