For five years, under the leadership of former prime minister Junichiro Koizumi, Japan's security relations with the United States solidified. Yet, over the past year, that alliance has lurched into a sharp decline under prime ministers Shinzo Abe and Yasuo Fukuda, because Tokyo has reverted to the insular politics of yesteryear.
At issue has been a cynical ploy by the leader of the Democratic Party of Japan, Ichiro Ozawa. He tried to use what he perceived as public disapproval of Japan's maritime support for the US in the Indian Ocean to force out Mr Fukuda, of the Liberal Democratic Party. Mr Fukuda, in turn, dallied in a half-hearted effort to bring Mr Ozawa around.
Both, it seems, misread public opinion. Polls taken by the Asahi, Yomiuri, Mainichi, and Nihon Keizai newspapers, and the Kyodo News Agency, found that between 44 per cent and 49 per cent of Japanese approved of Tokyo's naval deployments. In contrast, between 30 per cent and 43 per cent - a wider spread - disapproved. As the Economist magazine said in an editorial: 'So is this the Japan of old: self-absorbed, unashamed at leaving others to do the hard military tasks?'
Mr Fukuda, who has been in office less than two months, was forced to withdraw Japanese vessels from the Indian Ocean because he had been unable to persuade parliament to extend the law authorising them to refuel ships from the US and three other nations. In six years, Japan had carried out 780 refuelling operations.
A less visible airlift, in which Japanese military planes ferried people and cargo on 380 flights within Japan, has also ended. Lieutenant Colonel Scott Graham, a US Air Force operations officer, was quoted in Stars & Stripes, the military newspaper, as saying: 'It allowed us to dedicate our aircraft to other missions', including flights into Iraq and Afghanistan.
A year ago, Japan pulled its contingent of 600 soldiers out of Iraq, where they had been assigned non-combatant tasks. The Japanese had rotated 10 such units through Iraq for six months at a time, the first overseas deployment of Japanese soldiers since the second world war.
Moreover, several Tokyo press reports said that Mr Fukuda's government was planning to reduce its financial support for US forces in Japan when the fiscal year begins in April. Tokyo pays for most of the yen costs at US bases in Japan, such as rent, labour and utilities. That runs to between US$4 billion and US$5 billion a year, or about 10 per cent of Japan's military budget.
Into this valley of disarray rode US Secretary of Defence Robert Gates seeking to get the alliance back on track. He told Mr Fukuda, Foreign Minister Masahiko Komura and Defence Minister Shigeru Ishiba last week it was 'unfortunate' that the refuelling operation had been suspended and urged Japan to 'resume its leadership' in Asia.
US military officers have contended, somewhat anxiously, that the damage to the alliance would be limited to the political sphere. They said they expected agreements already reached with the Japanese, such as putting a US army corps headquarters in the Camp Zama base alongside a Japanese headquarters, to move forward.
Tokyo, moreover, has agreed to pay for 60 per cent of the US$10 billion cost of moving 8,000 US marines and 9,000 dependents and civilian employees to Guam from Okinawa, leaving less than 10,000 marines on Japan's southern island. That move is to be completed sometime around 2014.
Even so, the law of unintended consequences seems to be at work. Japan's emergence from the cocoon in which it had wrapped itself after the second world war has been brought into question. Tokyo's hopes of attaining a permanent seat on the UN Security Council have been set back.
The Asian Gateway Initiative, proclaimed by Mr Abe last spring, appears to be in jeopardy. It was to have eased Japan into a 'responsible role in the development of Asia' and allow it to take the lead in forging 'an open regional order', emphasising economic progress.
Just after he took office, Mr Fukuda said in a policy address: 'Maintaining the solid Japan-US alliance and promoting international co-operation are the foundation of Japan's diplomacy.' He pledged that 'Japan will realise its responsibilities commensurate with its national strength in the international community, and become a country which is relied upon internationally'.
Those aspirations have dropped below the horizon, at least for the immediate future.
Richard Halloran is a former New York Times foreign correspondent in Asia and military correspondent in Washington