TOKYO >> The five candidates vying to become Japan’s next prime minister promised Sunday to resolve the country’s nuclear crisis and revive its battered economy, amid widespread public cynicism about a revolving door of leaders.

Japan — which is set to see its sixth prime minister in five years — has fumbled recently to find leadership to tackle formidable challenges, including recovery from a massive earthquake and tsunami in March and the battle to bring a nuclear power plant sent into meltdown by the disasters under control.

Even before the disasters hit, the nation was already ailing with serious problems such as an aging population and stagnant economy.

None of the five candidates looking to replace Naoto Kan as prime minister is expected to win the needed majority of 200 votes in balloting among legislators in the ruling Democratic Party in the first round of voting, set for Monday. If no one gets a majority, a run-off between the top two candidates would follow.

The winner of the Democrats’ leadership vote is almost certain to become the nation’s next prime minister because the party controls the lower house of Parliament, which chooses Japan’s chief.

Public interest has been stunningly low, underlining the widespread disenchantment with politics.

A debate Sunday among the candidates was not carried live on any of the major TV networks.

“In Japan these days, a prime minister who lasts even one year is a miracle,” said Minoru Morita, who has written several books on Japanese politics.

He predicted more confusion ahead, including a possible split in the ruling party in coming months.

Japanese media reports said Sunday that Economy Minister Banri Kaieda, 62, had a slight lead over other candidates after securing the backing of the ruling party’s behind-the-scenes power broker, Ichiro Ozawa.

But that could prove a pitfall in a run-off, as legislators may rally behind a rival to block Ozawa’s grip on power, according to Morita.

Facing off against Kaieda are former Foreign Minister Seiji Maehara, Finance Minister Yoshihiko Noda, Agriculture Minister Michihiko Kano and former Transport Minister Sumio Mabuchi.

Maehara, 49, was initially considered the favorite until Kaieda won Ozawa’s backing.

Maehara has technically violated election laws by accepting donations from foreigners — a problem that could bring him down if the opposition decides to pursue that in parliament. He stepped down as foreign minister earlier this year over that scandal.

Legislators, therefore, may decide to support a relatively safe candidate such as Noda, said Morita.

“Some lawmakers are extremely afraid of Mr. Ozawa’s almost dictatorial power,” Morita told The Associated Press.

Ozawa, 69, a veteran who began in the long-ruling and now opposition Liberal Democratic Party, is known for savvily engineering elections, sending novices to parliament, as well as dooming candidates to defeat.

Ozawa is embroiled in a political funding scandal, though some say his trial is likely to end in acquittal, and his presence has hung like a shadow over the party leadership campaign.

At Sunday’s debate at a Tokyo hotel, candidates appeared in agreement, all promising a revived Japanese economy and a resolution of the nuclear crisis in comments heavy on rhetoric but scant on concrete proposals.

“I would like to use the recovery efforts in northeastern Japan as a springboard to achieve an overall revival of Japan,” Kaieda said, after invoking President John F. Kennedy’s famous line about asking what you can do for your country, rather than what your country can do for you.

No matter who wins, the new prime minister is expected to last barely a year because he would merely be serving out the term of Kan, who announced Friday that he would resign.

Kan, 64, came to power in 2010 amid high hopes for his liberal and approachable persona. But by the time he stepped down, his popularity had plunged.

Japanese are disappointed and frustrated by the apparent inept rule of the Democrats, who swept to power in 2009, ending a virtually continuous half-century rule by the Liberal Democrats and promising to help consumers, not just big business.

Soichiro Tahara, who hosts TV shows and has authored books, noted that Ozawa remains a powerful shadow shogun and expressed doubts that the next prime minister will get much done.

“Japan certainly isn’t headed to any bright future,” he said in a recent TV commentary.