By Linda Sieg
TOKYO (Reuters) - Japan's opposition Democratic Party elected former foreign minister Katsuya Okada as its leader on Sunday, turning to a familiar face to try to persuade voters it can again become a viable alternative to Prime Minister Shinzo Abe's ruling party.
Okada, 61, must try to repair the Democratic Party of Japan's (DPJ) battered image two years after Abe led his conservative Liberal Democratic Party (LDP) to power pledging to revive the economy and strengthen defense policies.
"I want to make the DPJ a party that the people believe can take responsibility for a change in government, and fight fairly and firmly with Abe's LDP," Okada told a party convention after his election to the post he held a decade ago.
A mix of former LDP members, ex-socialists and centrists, the DPJ surged to power in 2009 on a promise to focus on consumers rather than big firms and other vested interests.
But the Democrats fell prey to policy flip-flops and internal strife, changing premiers three times in three years.
They were trounced in the 2012 election that returned Abe to office and made minimal gains in a snap election last December that saw the LDP-led coalition keep its two-thirds lower house majority, albeit with record-low voter turnout of 53.3 percent.
Then-party leader Banri Kaeda lost his own seat. Three candidates ran in the race to succeed him - centrist Okada, left-leaning former health minister Akira Nagatsuma, and Goshi Hosono, 43, the most conservative and youngest of the trio.
All three had stressed the need to address widening economic disparities and welcome social diversity. They also criticized Abe's efforts to recast Japan's wartime past with a less apologetic tone, a stance that causes friction with China and South Korea.
Okada offered a 300-day party reform plan and a plan to demand Abe's cabinet rescind its controversial decision to ease constitutional constraints on the military's role abroad, Kyodo news agency said.
Critics worry Japan is returning to a pattern of one-party dominance, but the Democrats have not so far been able to tap into voter longing for an alternative to the LDP.
"The problem is the party has no shared core beliefs, has made no accounting for its miserable performance in government, and is unclear about what its policy priorities would be if it could take power again," said Columbia University professor Gerry Curtis.
(Additional reporting by Kaori Kaneko; Editing by Nick Macfie)