The abrupt departure of a prime minister would be high drama in any country, but in Japan, where politics generally moves at a predictable pace, the fall of Shinzo Abe was a sensation.

The range of possibilities it opens is thrillingly and alarmingly broad. By winter Mr Abe’s ruling Liberal Democratic Party could be under a more assured leader – most likely the lordly, nationalistic former Foreign Minister Taro Aso. It might be governing in some kind of coalition with its opponent, the Democratic Party of Japan (DPJ). Or, conceivably, it could fall out of power altogether, bounced out by the DPJ for only the second time in half a century.

Most likely it will still be in power, but bogged down in a grinding parliamentary conflict that will certainly last weeks and could drag on for months. Japan’s steady efforts to increase its engagement with the outside world – its dispatch of troops to Iraq and the Indian Ocean, the moves to revise the “pacifist” Constitution to make such missions easier, its push for a UN seat and its modest efforts to become involved in Middle East peacemaking – will be side issues until this central question is resolved: who rules Japanese politics? The LDP, which has been in power for all but a few months of the past 52 years? Or the newly empowered Democrats and their leader, Ichiro Ozawa?

The immediate causes of Mr Abe’s resignation are mysterious, but the broader pressures on him are understood easily. In July the LDP lost control of the Upper House to the DPJ, allowing it to delay Bills and cripple Mr Abe’s legislative programme. As a consequence, Mr Abe seemed likely to fail in an urgent task: the extension of a naval mission to the Indian Ocean.

But Mr Abe’s trouble began soon after he came to power last September. His first act – a visit to China and South Korea to mend relations damaged by his predecessor, Junichiro Koizumi – was a bold success. He passed a new education Bill, controversially promoting “patriotic” education.

However, his vision of a “Beautiful Japan” – a country defiantly unapologetic about its wartime past and imbued with conservative values of pride in nation, history and race – provoked unease in as many people as it inspired. And he failed utterly in day-to-day political management.

The indiscipline and scandals among his Cabinet ministers and senior appointees, of whom four resigned and one hanged himself, spoke of bad judgment, but also a lack of authority. When problems arose, Mr Abe was irresolute and unconvincing to an extent that made bad situations worse. It was not the fault of his Government that Japan’s social security agency, for example, lost 50 million pension records. But Mr Abe’s defensive shilly-shallying attracted, rather than deflected, blame and reproach.

Mr Koizumi, his predecessor, was one of the most gifted and exciting prime ministers since the war; with his reserved and dignified manner, Mr Abe was always put at a disadvantage by the comparison. But he came to power amid great excitement, particularly on the Right, and he was said to feel a sense of personal destiny in succeeding to a job held by his grandfather, Nobusuke Kishi, and narrowly missed by his father, Shintaro Abe. Now he will go down in history as one of Japan’s political also-rans, soon to be forgotten.

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