"Over the past four years, certainly U.S.-Japan relations have deepened. At the same time, there have been vast unopened, uninhabited areas of this relationship," said Kent Calder, director of the Edwin O. Reischauer Center for East Asian Studies, an affiliate of the School of Advanced International Studies at Johns Hopkins University.

"At the periphery of the security issues, even on some of the most important security issues themselves, and certainly with respect to broader economic questions, there remains much to be done," said Calder, who between 1997 and 2000 served as special assistant to U.S. Ambassador Thomas Foley.

Calder stressed the need for Japan and the U.S. to hold dialogue on energy issues -- with their links to security problems -- at a time of high energy prices worldwide and turmoil in the Middle East.

"Japan and the U.S. are both dependent on the global energy system, and yet the nature of their dependence and the implications for policy are significantly different," Calder said.

Japan is 99 percent dependent on imports for oil, compared to the roughly 50 percent for the United States. And while Japan depends on the Middle East for 80 percent of its oil, that region accounts for only 23 percent of America's oil imports, he noted.

"So there are significant differences in the nature of the energy problems they face," Calder said. Failure to correctly understand this, he added, could feed back into the bilateral alliance "in subtle but dangerous ways."

For example, it is widely known in Washington that China generated 40 percent of the increase in worldwide oil demand in 2003, he said. But people in the U.S. may not pay much attention to the fact that Japan remains by far the largest importer of oil in Asia, he added.

Also citing the role of nuclear power, the nuclear fusion reactor project, the Middle East, and sealane defense, Calder said there are "a whole host of energy issues that are also significant to economy and security . . . and more enhanced dialogue between the two countries will be valuable so that they actually are looking at these energy aspects of their broader relationship more clearly."

Edward Lincoln, a senior fellow at the Council on Foreign Relations who served as a moderator in the symposium, said the current "good" Japan-U.S. relationship may be emphasized too much.

There is a danger to this 'feeling good" atmosphere because "we could end up ignoring what are in fact important issues where we are not together. We need to understand the differences in how we approach issues," Lincoln said.

He cited Iran as one such issue.

"For the U.S., Iran is rising rapidly as a serious issue because of (its) efforts to pursue a nuclear arms option. What I hear from Japan...is if anything a rush of Japanese companies trying to do business in Iran before the U.S. stops them from doing it," he said, adding that the gap could partly be attributed to the differences in the nature of energy issues confronting the two nations.

Calder noted that in the long term, the relationship between Japan and Iran will be tremendously important, given Iran's huge oil and natural gas reserves.

"Japan can be very helpful, potentially, to the U.S. and the world in stabilizing the broader international relationship with Iran," he said.

But in the short term, Calder said, the crucial issue is the nuclear program. Japan would be well advised to postpone its project to develop the Azadegan oil field in southern Iran, so that nations can work together to have Iran drop its nuclear ambitions through closely coordinated pressure, he added.

Kurt Campbell, senior vice president of the Center for Strategic and International Studies, noted that Japan is not alone in trying to engage Iran commercially. In fact, many other countries have major projects in Iran, with the U.S. as the "odd man out," he said.

"The only way we're going to have success vis-a-vis Iran would be for Europe, Japan and the U.S. to alter their strategies," he said.

"Essentially today, Europe has offered just carrots and America has only offered sticks. If we are to be successful . . . Europeans have to be a little bit more threatening about what the potential consequences of continued nuclear provocation are, and the U.S. must put on the table a more positive vision for Iran if Iran takes steps to stop its nuclear ambitions," he added.

Fumiaki Kubo, a professor of law at the University of Tokyo, noted that even though they are close allies, it would be only natural for Japan and the United States to have differences on some issues.

Kubo also pointed out that while government-to-government ties have improved dramatically, Japan's public opinion toward the U.S., particularly the Bush administration, is not so favorable.

And while developments since the Sept. 11, 2001, terrorist attacks suggest that Japan will move in the direction of playing a greater role in the bilateral security alliance, it is unclear whether the Japanese public will support it, he noted.

Calder agreed that public opinion is vital for security policy. "Will the Japanese people be ready for an expanded role of Japan in the security alliance with the U.S.? Of course that is determined between leaders, but also needs to be something that is more broadly persuasive to the people of both nations," he said.

Calder noted that new people taking key positions for the second Bush administration could mean more opportunities for putting new ideas for bilateral ties on the table in the U.S. political process.

The panelists said the new U.S. ambassador to Japan, Thomas Schieffer, would do a good job here, given that U.S. relations with Australia improved while he was serving as America's envoy there over the past four years.

Campbell described Schieffer, Bush's longtime Texas friend and business associate, as a man who "could pick up a phone and in one minute get the U.S. president on the line" -- an asset that is more important than policy expertise for a job like ambassador to Japan.

Campbell meanwhile expressed concern about the personnel changes in Washington, particularly the departure of Richard Armitage as deputy secretary of state.

"The (first) Bush team was privileged to have the strongest hand of Japan specialists that the U.S. government has ever had," he said.

True, the close personal ties between President Bush and Prime Minister Junichiro Koizumi remain intact, but there needs to be people in the bureaucracy who "are equally committed to the pursuit of a stronger alliance," he noted. "With Armitage leaving, there is an enormous hole, and it's unclear who's going to step in and fill this vacuum."