By Linda Sieg and Yuko Yoshikawa
TOKYO (Reuters) - Growing Japanese opposition to nuclear energy after the Fukushima disaster will be a wild card in a general election many expect within months, but politicians on both sides of the aisle agree on one thing: the Democratic Party is likely to fall from power just three years after its historic landslide win.
A mix of conservatives, centre-left lawmakers and ex-socialists, the Democrats swept to power on a groundswell of hope for change in August 2009, promising to change how Japan is governed after more than 50 years of almost non-stop rule by the conservative Liberal Democratic Party (LDP).
Three years and three prime ministers later, critics say its pledges to reduce bureaucrats' control of policymaking and pay more heed to consumers and workers than corporations were honored mainly in the breach.
"The Democrats did not sufficiently achieve their campaign promises in the past three years. So for them to return to the opposition is the most likely outcome," Hajime Ishii, an upper house heavyweight in Noda's Democratic Party of Japan (DPJ), told Reuters in an interview.
Instead, Prime Minister Yoshihiko Noda has pushed ahead a plan to raise the sales tax to curb massive public debt and fund ballooning social welfare costs.
Legislation to double the sales tax by 2015 passed the lower house in June with the backing of the LDP and its one-time coalition partner as well as the DPJ, but that sparked a string of defections from the ruling party.
FORCING NODA'S HAND
Keen for an early election, the LDP is threatening to submit a non-binding censure motion against Noda in the opposition-controlled upper chamber, which could halt deliberations, or present a no-confidence motion in order to force the premier's hand.
The DPJ still has a slim majority in the lower house, but that could evaporate if more defect.
"The feeling is growing day by day that we cannot leave the governing of Japan to the Democrats any longer," LDP Vice President Tadamori Oshima told Reuters.
"In order to create an opportunity for a judgment on the Democrats' three years in office and to obtain a public mandate for the three-party agreement (on the sales tax), we want to use either a censure motion or a no-confidence motion."
No one expects lower house members to serve their full four-year terms through August 2013 but the Democrats appear eager to put off the day of reckoning as long as possible.
On Friday, Noda played his cards close to his chest. "I don't mention election timing even when I talk in my sleep," he said in an interview with Japanese media.
Whatever the timing, the DPJ risks facing an anti-nuclear backlash as protests grow against Noda's decision to restart two atomic reactors to avoid blackouts, despite safety fears after an earthquake and tsunami crippled the Fukushima nuclear plant in March 2011 the world's worst nuclear disaster since Chernobyl in 1986.
Which parties would benefit, though, is unclear. The Democrats' main rival, the LDP, promoted atomic power during decades of dominance and only the tiny Social Democrats, the Communist Party and a DPJ splinter group led by ex-party leader Ichiro Ozawa are clearly against ending nuclear power soon.
Populist Osaka Mayor Toru Hashimoto, whose Ishin no Kai (Restoration Group) local party is eyeing a national role, had to backtrack on an early anti-nuclear stance when he signed off on nuclear reactor restarts to avoid possible summer blackouts.
"I'm sure a bunch of people will vote against nuclear power no matter what, but how many are willing to go that far (to vote for the Social Democrats, Communists or Ozawa's new group)?" said Steven Reed, a political science professor at Chuo University in Tokyo. "They've never been given a proper option."
Predicting the election is tough given Japan's fragmented political scene, where new parties are springing up like mushrooms as voter disaffection with mainstream groups grows.
That public disaffection was apparent even in the rural conservative stronghold of Yamaguchi, western Japan, where an anti-nuclear candidate came in a strong second to an LDP old guard rival in an election for governor last Sunday.
The LDP's Oshima said it was possible his party and former partner, the New Komeito party, could win a majority, but others are betting a broader coalition will need to be built, threatening another bout of wobbly and indecisive government. Japan has already had six premiers since 2006.
Hashimoto's Ishin no Kai could do better than expected as a focal point for voter dissatisfaction, while a "grand coalition" of the LDP and DPJ can't be completely ruled out.
A DPJ-led coalition would be a long-shot, though not impossible, the politicians said.
"Whatever the results, the next government is likely to be a multi-party coalition and may well not be able to decide policies," said Hiroykuki Sonoda, a lawmaker in the tiny opposition Sunrise Party who has been in and out of the LDP since starting his career as a lawmaker in 1986.
(Editing by Nick Macfie)