AT THE heart of Ichiro Ozawa's constituency near Oshu City in north-east Japan stands the huge Isawa dam, built of rock. It looks like a monument to the political career of a man fighting against the odds to become Japan's latest prime minister on September 14th. It deserves to be the millstone around his neck.

Conceived in the early 1990s when Mr Ozawa first cast himself as a reformer of Japanese politics, the dam has cost an estimated 244 billion yen ($2.9 billion) yet is still unfinished. Ostensibly its purpose is to provide more irrigation for local rice paddies, and some hydroelectricity. But the impetus its construction has given to the local economy has also helped to keep Mr Ozawa in parliament for the latter part of his 41 years as an MP.

Known as the Ozawa dam—Isawa and Ozawa sound mischievously similar in Japanese—it, like him, is popular locally (the main dish in a nearby restaurant is called “Dam Feast”). The 68-year-old has been one of Japan's most prominent political reformers, masterminding a landslide election victory by the Democratic Party of Japan (DPJ) last year and encouraging new electoral rules, for example promoting transparency in fund-raising, since he first galvanised opposition politics in 1993.

Yet the dam represents the dark side of Mr Ozawa, too. Analysts say his championing of large public-works projects to further his own political ambitions, and his personal disregard for the new rules that he helped put in place, show how he remains a throwback to the “money-power” politics that helped to keep the Liberal Democratic Party (LDP) in government for half a century. “In so many ways Ozawa's modus operandi is reminiscent of all the bad old ways of LDP politics, which ultimately disqualifies him as a reformer,” argues Aurelia George Mulgan, a Japan expert at the University of New South Wales, in a new paper. She calls his leadership style “imperial”.

Money politics may yet bring him to court, too. In January three of his former secretaries were arrested and charged over a land deal in Tokyo that prosecutors, reportedly, suspect might have violated political-financing laws and was part-funded by a construction company working on the Isawa dam.

Though Mr Ozawa has repeatedly denied knowledge of any murky transactions, he was forced to resign from a high-ranking position in the DPJ in June partly because the scandal was damaging the government's popularity. Prosecutors have twice decided not to press charges against him over the land purchase. But if an inquest into their investigation rules for a second time that he should be indicted (it has already done so once), then he will automatically be charged. Provided, that is, that he is not by then leading the cabinet or part of it, in which case he could by law claim immunity from prosecution.

Despite the scandals Mr Ozawa remains neck-and-neck with Naoto Kan, the prime minister, ahead of a September 14th election to head the DPJ, which in effect decides who will be prime minister. Even some of Mr Ozawa's supporters concede that Mr Kan is marginally more likely to win, because he enjoys more popular support and the nation is sick of a succession of fly-by-night leaders. But Mr Ozawa's chances are bolstered by his following among loyal DPJ parliamentarians, most of whom have benefited from his political patronage as well as his personal nurturing. MPs' votes carry the most weight.

The reason why so many of Mr Ozawa's supporters stick by him shows what an important, and potentially troubling, battle this is for Japan. It appears to be the dominance of pragmatism over principle, and old-style back-room bargaining over more accountable, albeit potentially slower-moving, politics.

One of his most prominent supporters, Goshi Hosono, the DPJ deputy secretary general, ruefully acknowledges Mr Ozawa's links to “old-money politics”. But he says that he sees Mr Ozawa as a radical reformer who can build bridges with opposition parties, such as the LDP. He believes that without Mr Ozawa's leadership, there would be further paralysis in Japan's hung parliament. Mr Kan may lack his skills.

The boss of a leading construction company in northern Japan talks of Mr Ozawa as a potential saviour, hoping he will be like a samurai strongman who can jolt the moribund economy back to life through massive public-works projects. “At a time like this, you don't need the clean guys, you need the guys who can get things done,” he says. “Ozawa has excelled at getting public works in the countryside. He knows how much rural Japan needs reviving. Most people in the construction industry know he will provide the adrenalin injection quickly.”

Contradictory man

Such talk, however self-serving, shows the fragility of the transition from the long dominance by the LDP to a more dynamic system. It also reveals a scepticism that Mr Kan, if he wins, could implement significant reforms that can pull Japan out of two decades of stagnation. Analysts fear that if Mr Ozawa loses, he may bolt from the DPJ, making it even harder to pass legislation—though Mr Hosono insists the party would not split. A rupture would deepen what Gerald Curtis, a Japan scholar at Columbia University, already calls “a gridlock worse than anything Japan has experienced in half a century”.

But a victory by Mr Ozawa might represent a return to the informal power networks in Japan, which operate away from public scrutiny and accountability. As one former construction-industry boss puts it, Mr Ozawa is not in politics to get rich, but to get power—and money is his means to power. He is already rich: Kyodo news agency this year suggested that Mr Ozawa and his wife, the daughter of a construction magnate, together have assets of almost 2 billion yen, including villas and land in six prefectures, giving him a large potential war chest. But if he wins power, his record is so contradictory it is not clear if he would rule to serve the narrow interests of his clique, or the pressing needs of the country.