The row over relocating the Futenma air base on Japan's southern island of Okinawa is straining ties between the United States and Tokyo's new government, which has vowed to steer a more independent diplomatic course from its security ally..

Entangled with the feud, however, are deeper questions about whether Obama and Prime Minister Yukio Hatoyama, whose Democratic Party ousted its long-dominant conservative rival in an August poll, can start to reframe a nearly five decade-old alliance that has been at the core of security arrangements in Asia.

Obama will visit Japan on Nov. 12-13 as part of his first tour of Asia since taking office.

“We have a multi-polar system emerging. You cannot deny the fact that the rise of China is now seen as an essential element (of that system),” said Hitoshi Tanaka, a former senior Japanese diplomat who advises some Democratic Party lawmakers.

“In 1996, I felt that when you dealt with a specific but important question like Futenma, we had to put it in the larger context,” Tanaka said, recalling the last alliance review when the two nations tightened security ties after years of bitter trade disputes.

“I have a feeling we need to engage in the same thing,” he said, proposing the two countries reassess the alliance, its goals and the countries' respective roles over the coming year.

Hatoyama told parliament on Thursday he wanted to conduct a comprehensive review to create a multilayered alliance long term.

While the process would likely be bumpy, many agree the alliance, while vital to both partners, needs a rethink.

“There is more raison d'etre to the alliance than ever before, but they have to reframe it and take it out of the Cold War context,” said Daniel Sneider at Stanford University's Shorenstein Asia-Pacific Research Center.

With China forecast to overtake Japan as the world's second-biggest economy as early as next year, concerns in Japan that Washington will cozy up to Beijing in a “Group of Two” (G-2) that leaves Tokyo out in the cold are never far from the surface.

“That idea sends shivers down Japanese spines,” said Richard Samuels, a Japan security expert at the Massachusetts Institute of Technology (MIT).

The feud over Futenma has fanned such fears among Japanese conservatives, who say Hatoyama risks mismanaging the matter.

Tensions rose after U.S. Defense Secretary Robert Gates bluntly told Tokyo this month that he wanted a 2006 pact to replace Futenma with a facility in a less crowded part of Okinawa and shift 8,000 U.S. Marines to Guam to go ahead as planned.

The deal was part of a broader agreement on reorganizing the 47,000 U.S. military personnel stationed in Japan.

“China wants to show the world it is a positive partner of the United States,” said Hitoshi Hirabayashi of the Japan Forum on International Relations. “If Japan continues to hesitate or kills time by hesitating, the Americans may naturally be induced to think that Japan is finally not the best partner.”

Across the Pacific, some in Washington are equally worried by signs that Japan is distancing itself from its closest ally by promoting an as yet ill-defined East Asian Community.

Suggestions by some Japanese experts that the U.S. military presence in Japan is outdated also worry some in Washington.

“The fact that a foreign military continues to exist in an independent country means that the 'post-war era' has not ended,” Jitsuro Terashima, chairman of the Japan Research Institute, who is said to have Hatoyama's ear, said on television recently.

Hatoyama sought to allay U.S. concerns last weekend by telling a summit of East Asian leaders in Thailand that Japan's alliance with Washington was at the heart of Tokyo's diplomacy.

Former diplomat Tanaka said Tokyo needed to do a better job of explaining its policies.

But he added that a stronger focus on East Asia was inevitable given Japan's shrinking, ageing population, and should not be viewed with dismay by the United States.

“If you look at all the trade statistics, investment, the movement of people, you would no longer just target the United States as your most important economic market,” he said.

“We have to survive as a prosperous nation and for that we need East Asia to become a much more vibrant place.”

Other efforts by Japan's Democrats to reassess policies put in place by the ousted Liberal Democratic Party during its half century of almost unbroken rule are also potential flashpoints.

An investigation by Japanese Foreign Minister Katsuya Okada into a decades-old “secret agreement” between Washington and Tokyo that effectively allowed nuclear-armed U.S. vessels to enter Japan has sparked concern. So has Okada's proposal that the United States should promise not to use nuclear weapons first.

Japan, the only country to suffer an atomic bombing, has long had an ambivalent stance on nuclear arms. Successive LDP governments have stuck to a ban on nuclear weapons but relied on the U.S. “nuclear umbrella” for deterrence.

Despite current concerns, many experts dismiss the notion that a communist China could replace democratic Japan as America's closest Asian partner — even as they point to the need to broaden the alliance beyond traditional security ties to areas such as fighting global warming and disaster relief.