Some experts have said that the 68-year-old, who favors spending to stimulate the economy, could be biding his time to stage a political comeback if Prime Minister Naoto Kan flounders with policy deadlock in a divided parliament.

Ozawa lost to Kan in a Democratic Party of Japan (DPJ) leadership race in September, but many credit him with engineering the party’s election victory in 2009 that ended more than 50 years of almost non-stop rule by the Liberal Democrats.

Ozawa’s backers say he has the leadership and skills to break through Japan’s stalemate, although ordinary voters have been put off by his scandal-tainted image and his reputation as an old-style autocrat who wields power from behind the scenes.

A judicial panel of ordinary citizens decided that Ozawa be charged over the funding scandal. The move means the courts must appoint lawyers to prosecute the case.

“It’s very disappointing. I am confident that the trial will show that I am innocent,” media quoted Ozawa as saying in a statement.

Ozawa heads the biggest group of lawmakers in the DPJ but his influence was diminished when Kan won the party leadership vote after overwhelming support from its rank and file. Ozawa’s influence could be further dented when he is charged.

“It would delay a comeback,” said Koichi Nakano, professor at Sophia University.

“As long as the court case goes on, he’s not going to be able to come back to the front line,” he said, but added that if Ozawa was found not guilty, his career would not be over.

Seishu Makino, the DPJ’s deputy head of parliamentary affairs, said Ozawa should leave the party.

“I think that he should step aside himself if (the judicial panel) says that he should be charged,” he said. “If that is not possible, then we, as a public party, need to draw a clear line.”

Ozawa, in his bid to topple Kan last month, had called for spending to stimulate the economy if needed, even if that meant adding to public debt, which is already twice the size of Japan’s $5-trillion economy.

He has also been less willing than Kan to debate a future increase in the 5 percent sales tax to fund bulging social welfare costs, arguing that the government needs first to weed out wasteful spending.

While some experts warn of Ozawa’s history of breaking up parties he once led, many have doubted that he would split the DPJ.

“Even if Ozawa were to leave the party, not many would follow him, especially since the DPJ is in power,” said Tetsuro Kato, political science professor at Waseda University.