His candidacy for the post was made clear when he paid a social call on a group of first- and second-termers of the House of Representatives, most of whom are close to former party leader Ichiro Ozawa.

That Ozawa and Mabuchi are first out of the blocks is not surprising. Unfortunately for Ozawa, he is burdened with his last name, which confuses him with the far more famous former party leader Ichiro Ozawa. As for Mabuchi, he has only three elections to the Diet — far too few for a formal candidate for the party’s top post. He was also censured this winter by the Liberal Democratic Party-led House of Councillors, an act that triggered Mabuchi’s eventual resignation as vice minister. That a man so recently condemned by the House of Councillors will be expected to work with the members of that House to pass legislation baffles the mind.

Beyond Ozawa and Mabuchi there are a host of candidates to replace Kan including Chief Cabinet Secretary Yukio Edano, Minister of Finance Yoshihiko Noda, Minister of Agriculture Michihiko Kano, , Minister for Economics, Trade and Industry Banri Kaieda, and Minister for National Strategy Gemba Koichiro. All have remained understandably silent about their plans because they are currently members of Kan’s Cabinet. Edano was once seen as a shoo-in thanks to his performance as the Cabinet’s chief spokesman in the initial days and weeks after the 11 March disasters. His star has since faded as the Kan government has had to make excuses for bungled responses to the Fukushima disaster. Kaieda, who was seen as having a trump card in being an Ichiro Ozawa favorite, may have blown all chances of his ever becoming prime minister due to a recent stunning on-camera breakdown whilst testifying in Diet committee.

In answer to who would be the people’s choice in the non-existent national election of a DPJ leader, among its respondents Kyodo News found (in percentages):

Seiji Maehara 21.2
Katsuya Okada 15.8
Yukio Edano 15.6
Kazuhiro Haraguchi 3.9
Yoshihiko Noda 2.9
Sakihito Ozawa 2.3
Sumio Mabuchi 1.6
Yoshito Sengoku 1.6
Koichiro Gemba 1.3
Michihiko Kano 0.7
Shinji Tarutoko 0.6
Somebody else 3.2
Don’t know/can’t say 29.3

Former Foreign Minister Seiji Maehara comes out the surprise winner — surprise because he has not been in the news much since his resignation as foreign minister over a very small illegal campaign contribution made to his political support group. While he is well-liked, and seen as a steady hand particularly in security affairs, he is burdened by a reputation of being a quitter. In this poll he is also probably benefiting from the votes of those who, given the choice, would vote for LDP members Shigeru Ishiba and Nobuteru Ishihara — like Maehara, hawks on security issues. But despite his faults and current silence, Maehara will definitely be in the running when the time comes. He has the ability to perform on camera, has served in several important party leadership and Cabinet positions, and has no real enemies. He is also currently outside the Cabinet, which will be seen as a positive when the deeply unpopular Kan Cabinet is dissolved.

DPJ Party Secretary Katsuya Okada, despite the seemingly high level of public support, has a near zero chance of running for the top spot. First, as the party secretary general he bears equal blame with Kan for the DPJ’s recent string of electoral failures. Second, he has just sold out the party’s core program of direct payments of cash to all families with children, signing an agreement with the LDP to essentially abolish the program, making him essentially unelectable. Koichiro Gemba, who in his role as the DPJ’s director of policy research co-signed the agreement with the LDP, has similarly taken himself out of the running for the party presidency.

Former Minister of Internal Affairs Haraguchi is always portrayed in the media as a strong candidate for the premiership. He has certainly never hidden his ambition to become party leader and PM. However, he is seen as the stalking horse for the return to power of Ichiro Ozawa — an outcome that the current leaders are at pains to prevent. Ozawa is not as influential as he was in the immediate aftermath of the 2009 House of Representatives election and during the premiership of Yukio Hatoyama, when he ran party affairs and government policy almost without opposition. His hold upon the youngest members of the party, while still substantial, has faded as he fights off an indictment on political corruption charges.

Deputy Chief Cabinet Minister Sengoku is, like Haraguchi, a decidedly ambitious individual. Unfortunately, he has shown himself to be immune to complaints about the electoral consequences of his comments and actions. He would hardly seem the person the rank-and-file would want in power when they face the public at the polls. He is also tarred, like Mabuchi, with the brush of having been censured by the House of Councillors regarding the government’s response to the arrest of a Chinese fisherman for ramming Japan Coast Guard vessels.

Shinji Tarutoko, despite his obscurity, ran against Kan in the party leadership contest of June 2010. His surprisingly strong second-place finish remains the reason he is still mentioned as a possible party leader. But the bulk of his support in the 2010 election was anti-Kan votes from members of the Hatoyama and Ichiro Ozawa groups inside the party. On his own now, Tarutoko’s chances are slim.

But weighing all this up ignores the elephant in the room: whoever wins the party leadership election and subsequently the post of prime minister will still be opposed by a do-nothing LDP–New Komeito–Your Party majority in the House of Councillors. This majority has already demonstrated it will do everything in its power to halt or even reverse the policy program of the ruling DPJ. Whilst LDP and New Komeito leaders have promised greater cooperation with the DPJ, once Kan steps down there is no indication the opposition will follow through on its promises. Indeed with the public opinion polls showing the LDP likely to flatten the DPJ if an election were held today, the LDP and its collaborators in the House of Councillors would be fools to not tie up government business to the point that the next prime minister, out of desperation, dissolves the Diet and calls for new elections.

So despite the flurry of activity and the promises of a better Japan, once Kan steps down as prime minister the deadlock in the Diet will almost certainly continue, preventing the government from addressing Japan’s immediate and long-term challenges, and further distancing the public from the political classes.

 Michael Cucek is Research Associate at the Center for International Studies, Massachusetts Institute of Technology. He writes about Japanese politics at the Shisaku blog.