Yasuo Fukuda, at 71, has become prime minister at a time when Japan is facing hard choices, both in domestic and foreign policy. An early crunch will come in the lower house of parliament, where authorisation for Japan’s maritime deployment to the Indian Ocean runs out on 1 November.

This operation consists of supplying fuel and water to US and other warships engaged in the war in Afghanistan, and has the authority of the UN Security Council. Indeed, this authorisation was extended recently, with new words of appreciation for maritime operations. That was an effort, by the US and others, to give Fukuda the political backing he needs at home to continue the deployment.

Fukuda, in the lower house of parliament, is facing an opposition emboldened by the huge victory of the Democratic Party of Japan in July’s upper house election. The DJP is a mish-mash of former members of the ruling party, and what is left of the socialists. It is led by an opportunist, Ichiro Ozawa, aged 65.

In the 1990-91 Gulf War, Ozawa made a name for himself by saying Japan must become a “normal” nation, and should support military interventions to preserve international security, provided they had a Security Council mandate.

But now Ozawa says Japan’s naval operations in the Indian Ocean are “illegal”. He is using this issue to try to force Fukuda to new elections for the lower house, which are not due until September 2009. Fukuda is unlikely to agree to that. If he goes to the polls now, he is likely to lose.

Japanese voters, fed up with faltering economic growth that does not seem to be trickling down at all, and incensed by a scandal in which the bureaucrats lost some fifty million pension records, are likely to vote against incumbents. But neither will Fukuda want the embarrassment of having to cave into Ozawa on an important foreign policy issue.

Even if the LDP extends the current parliamentary session, due to end 10 November, there is likely to be a hiatus in Japan’s Indian Ocean deployment. That will not go down well in the United States. Or indeed in Germany, which is now urging greater NATO efforts in Afghanistan, and has already had thirty soldiers killed there. And even France, galvanized by the risk that the US might lose in Iraq and Afghanistan, is contemplating a return to NATO’s Combined Command.

A bold Japanese leader such as Junichiro Koizumi might stick it to Ozawa, hoping to expose his opportunism and the divisions within his own camp. But nothing in Fukuda’s background suggests he is a risk-taker.

Indeed, Japanese politicians are not accustomed to making hard choices in security policy. That is because during the Cold War, they were not required to make any.

As long as the Cold War lasted, Japan was able to enjoy US strategic protection while undertaking few risks and costs. Japan’s leaders knew that United States needed bases in Japan from which it could credibly threaten Moscow that war in the west would also mean war in the east. All that Japan was required to do was refrain from restricting US operations out of the bases.

Japan also ensured that, while sheltering under the US nuclear umbrella, it would not risk being entangled in “America’s wars”. Thus the unelected Cabinet Legislative Bureau was allowed to rule that while Japan was entitled to engage in collective self-defence, the right of any member of the UN under section 51 of the Charter, it chose not to exercise the right.

True, there was some important military co-operation over the Japan Sea in the 1980s, at the height of the “second Cold War”. In fact, US and Japanese navy pilots flew subhunting missions over the Japan Sea, on alternate days. They were fully armed and ready to fight, as the Soviets well knew. Thus Japan could engage in collective self-defence if it suited its interests to do so.

But this was all over the horizon as far as the government in Tokyo was concerned, and it did not become known to the Japanese public. Thus divisions among the Japanese conservatives, papered over at the time of the Korean War, remained submerged as long as the Cold War lasted. But they are now re-emerging with a vengeance. Moreover, many issues in the US alliance remain unresolved, including the relocation of the Marine Corps air station at Futenma on Okinawa.

US alliance managers hope that Japan can become a “reliable ally’, and thus America can deal with a “rising” China on the basis of a reinvigorated alliance with Japan. But after a period of reinvigoration of the alliance under the leadership of Junichiro Koizumi, it now seems set for a period of further drift.

When the dust settles in Iraq and Afghanistan, the United States is likely to take a hard look at the worth or otherwise of its alliances. If Japan looks as if it wants to retain all the benefits of alliance while paying few of the costs, will Japan invite the abandonment that it most fears?