Poor Shinzo Abe. The Japanese prime minister's announcement that he's stepping down marked the end of an ignominious year. His term has been marked by just about every kind of political misfortune you can imagine – corruption scandals, crossed signals, stunning errors in political judgment, and just plain chaos. In the end, though, his fate was determined by the same weakness that has claimed so many illustrious victims before him: support for President George W. Bush and America's war on terror.

Wait a minute – wasn't Japan supposed to be one of the few pro-American countries left on the planet? The place where polls consistently show majorities expressing support for U.S. policies?

 (photo: Reuters)

Well, yeah – but only up to a point. Japan's citizens seem to like being America's allies when they're enjoying the protection of its soldiers and sailors, but they prefer to enjoy those prerogatives when the risks entailed in the process are kept as small as possible. For most of the postwar period Tokyo's side of the deal involved providing military bases and paying out large dollops of cash – a sacrifice that was sometimes irritating but essentially tolerable. In recent years, though, the terms of the bargain have been shifting – largely thanks to a new generation of conservative leaders who feel that the time has come for Japan to play a more active role in world affairs.

It was Abe's predecessor, the charismatic Junichiro Koizumi, who first pledged Japan's support for Washington and its Global War on Terror. It was Koizumi who sent Japanese troops to Iraq (they have since departed), and it was he who first approved sending Japanese ships to the Indian Ocean to refuel American and allied naval vessels operating there as part of the war in Afghanistan. Both of these moves were quite daring in view of Japan's pacifist constitution, which basically bans involvement in any sort of overseas military deployments. Koizumi got around that by getting parliament (controlled by his own ruling Liberal Democratic Party) to pass special laws enabling both of the measures. As Koizumi saw it, Japan needed to show that it could do some of the same heavy lifting that other American allies – like the UK, say – routinely perform. In return, presumably, Japan could gain America's support in containing China's geopolitical ambitions and North Korea's nuclear threat.

Abe, in turn, came to power last year pledging even more assertiveness. He proposed amending the constitution – particularly the parts of it that limit Japanese power projection overseas – and expanding Tokyo's capabilities to come to the help of its allies in times of crisis. So he was acting entirely in form when he announced, at the end of an Asia-Pacific summit meeting in Australia earlier this week, that he was staking his premiership on the success of his efforts to push through an extension of the special law  allowing the Indian Ocean refueling operations. If he couldn't get parliament to approve the law, he would resign – and it soon became clear that he had made a corresponding promise to none other than the American president during a tête-à-tête in Sydney.

Under the right conditions that might have sounded like a brave, principled stand. There was just one problem: the political opposition. Earlier this year the Democratic Party of Japan earned a crushing victory in an election to parliament's upper house. The DPJ had won by telling voters that Abe was ignoring countless problems at home – endangered pensions, widening social inequality, shaky health care – in favor of half-baked overseas adventures and dreams of diplomatic grandeur in league with the Americans. It was a highly effective pitch – and particularly in light of Abe's inability to communicate a convincing rationale for his plans to reform Japanese foreign policy. In the wake of his party's victory, Ozawa was soon declaring that he would do everything in his power to bring Japanese forces home from the Indian Ocean as soon as the special law expires on November 1. And so it was that, after his public pledge in Sydney, Abe returned to Tokyo and proposed negotiations with the DPJ on the issue. He was rebuffed – and, it is said, realized that he could not keep his promise to Bush. This was either a stunning miscalculation or a clumsy form of political suicide.

The day of Abe's announcement was a day of surprises. Virtually no one in the Japanese political class expected Abe to throw in the towel so soon – with nary a move to push through the extension. (Ozawa himself declared he had never seen anything like it his forty-year career as a politician.) And with that Japan's latest prime minister has joined the ranks of his colleagues already brought low by toxic proximity to Bush's policies. Spain's Jose Maria Aznar, Italy's Silvio Berlusconi, and Britain's Tony Blair all found themselves pushed out of  their premierships when their policies of support for the U.S. lost traction with their own domestic constituents. Who would have thought that a Japanese prime minister would find himself in their company?