Secretary of State Hillary Rodham Clinton today begins her first trip to Asia since taking office, with security issues high on the agenda. Lots of pretty diplomatic words can be expected from her and the Chinese, Japanese, Indonesian and Korean leaders with whom she confers.

Those suave utterances, however, will mask stark underlying realities that affect the security posture of the U.S. in Asia. Those realities may confront Clinton with difficult questions.

In Beijing, senior officers in the People's Liberation Army have been testing U.S. resolve for at least a dozen years. One after another commander of U.S. forces in this region has felt it prudent to caution the Chinese neither to miscalculate nor to underestimate American determination to remain a power in the Pacific.

Moreover, the government of President Hu Jintao and the Communist Party are beholden to the PLA to stay in power. They have become uneasy because the international economic crisis, China's own faltering economy and repeated outbreaks of civil unrest have brought into question their mandate to hold office.

Clinton has indicated she plans to take a firm line with the Chinese. In written answers during her confirmation hearings, she said: "This is not a one-way effort. Much of what we will do depends on the choices China makes about its future at home and abroad."

The Japanese government is even weaker, having had three prime ministers since Prime Minister Junichiro Koizumi stepped down in 2006. The approval rating of the incumbent, Taro Aso, hovers around 20 percent and his ruling Liberal Democratic Party may be voted out within this year.

That has almost paralyzed Japan's ability to respond to American appeals that Tokyo play a greater role in regional security. For their part, Japanese officials say they are worried about President Obama's commitment to Japan and are concerned that the new president will bypass Japan in favor of improved ties with China.

In South Korea, recent governments, including that of President Lee Myung-bak, have not decided whether to continue their nation's alliance with the United States or to complete a free-trade agreement with the U.S. Nor have they determined what sort of relations they want with China. In addition, South Koreans no longer seem intent on reunifying the peninsula because absorbing North Korea would be enormously expensive.

Only on hatred and distrust of Japan do a majority of South Koreans seem to agree. Japan's foreign minister, Hirofumi Nakasone, met with his Korean counterpart, Yu Myung-whan, in Seoul on Wednesday but they did little except to issue platitudes on economic cooperation, with a vague reference to a Korea-Japan research program "to deal with Korean-Japanese history."

This animosity constitutes the weakest link in the U.S. security posture in Asia as the U.S. has defense treaties with both nations — whose military forces barely talk to each other. This is not a trilateral alliance.

Not on Clinton's itinerary is North Korea but it will be lurking in the background. It has become clear that Kim Jong Il, Pyongyang's leader, has no intention of giving up nuclear weapons. Moreover, he may order the test of another ballistic missile soon. And he has renewed his belligerence toward South Korea.

Indonesia, the world's most populous Muslim nation, may turn out to be the brightest stop on Clinton's journey. Jakarta's politics seem to be settling down after much turbulence, economic damage is no worse than elsewhere, and President Obama lived there as a child.

Perhaps most important, U.S. and Indonesian military services have begun to rebuild good working relations and Indonesia has been cooperating with Singapore and Malaysia to fight terror and piracy.

A footnote: Most presidential and Cabinet-level excursions abroad go directly from point to point. Clinton, however, will fly 3,600 miles south from Tokyo to Jakarta, then fly 3,300 miles north to Seoul, before veering off to China. (It's 2,560 miles from Honolulu to Los Angeles.) A spokesman said the route was dictated by the availability of Asian hosts.

Maybe there's another explanation: An old Chinese tactic for dealing with foreigners is to "keep the barbarians waiting at the gate." Beijing may have inconvenienced Clinton to put the American supplicant in her place.

Richard Halloran, formerly with The New York Times as a foreign correspondent in Asia and military correspondent in Washington, is a freelance writer in Honolulu.