Tokyo ? Japan’s newly empowered leader Yukio Hatoyama rushed to select Cabinet ministers today after his party trounced the ruling conservatives in elections, sending them out of power for only the second time in 54 years.

Hatoyama said in a victory speech late Sunday that he would focus on making a quick and smooth transition, and said his priority was choosing the nation’s next finance minister.

Official results were still being counted, but exit polls by all major media said Hatoyama’s Democratic Party of Japan had won more than 300 of the 480 seats in the lower house of parliament. That would easily be enough to ensure that he is installed as prime minister in a special session of parliament that is expected to be held in mid-September.

Prime Minister Taro Aso, conceding defeat, said he would step down as president of the ruling Liberal Democratic Party.

Although the vote gave the Democrats a landslide win, most voters were seen as venting dissatisfaction with the ruling Liberal Democratic Party more so than endorsing the policies of the opposition.

The Democrats will also face next year an election for the less powerful upper house of parliament. They have controlled that chamber with two smaller allies since 2007, but if they fail to deliver quickly on their promises the ruling party could resurge.

The task ahead for the Democrats is daunting.

Japan managed to climb out of a yearlong recession in the second quarter, but its economy remains weak. Unemployment and anxiety over falling wages threatens to undermine any recovery. The jobless rate has risen to a record 5.7 percent. After a rapid succession of three administrations in three years, Japan is facing its worst crisis of confidence in decades.

In the long-term it faces a bleak outlook if it isn’t able to figure out how to cope with a rapidly aging and shrinking population. Government estimates predict the figure will drop to 115 million in 2030 and fall below 100 million by the middle of the century.

The Democrats’ solution is to move Japan away from a corporate-centric economic model to one that focuses on helping people. They have proposed an expensive array of initiatives: cash handouts to families and farmers, toll-free highways, a higher minimum wage and tax cuts. The estimated bill comes to $179 billion when fully implemented starting in the 2013 fiscal year.

The party has said it plans to cut waste and rely on untapped financial reserves to fund its programs. But with Japan’s public debt heading toward 200 percent of gross domestic product, the Democrats’ plan has been criticized as a financial fantasy that would worsen Japan’s precarious fiscal health.

Japan’s stock market surged early in the morning on the news of the election, but then fell back.