Victories for the Democratic Party of Japan in Sunday's Upper House by-elections in Kanagawa and Shizuoka prefectures show that the party is still enjoying solid support some 40 days after the inauguration of the DPJ-led government. The elections were the first Diet-level elections since the Aug. 30 Lower House election.

Sunday's results also show that the Liberal Democratic Party, which was routed in the Lower House election, failed to seize its first opportunity to regain some lost ground.

With the latest wins, DPJ members now number 115 in the 242-seat Upper House, seven short of a majority. The number could serve as a springboard for the party's efforts to gain control of the chamber in the full Upper House election next summer so that it doesn't have to rely on help from other forces.

The DPJ's Upper House parliamentary group, including those other groups cooperating with the DPJ, now has 120 members — only one seat shy of a voting majority (Upper House President Satsuki Eda is a DPJ member but does not vote). If the DPJ can get enough independents on board, it will be able to pass bills even if the Social Democratic Party, one of its coalition partners, rebels.

Despite the DPJ's triumph in Sunday's two by-elections, Prime Minister Yukio Hatoyama will not have an easy time in the Diet right off. He first must clear up the problem surrounding how his fund management organization handled political donation reports. If he fails to fully explain himself to voters' satisfaction, public support for him and his party could tail off quickly.

He also must tackle sensitive issues such as the relocation of the U.S. Marine Corps' Futenma Air Station on Okinawa Island, the reconstruction of Japan Airlines, the plan to abolish the Yanba dam project, and the reduction of the fiscal 2010 budget-request total, which now exceeds ¥95 trillion.

On the other side of the house, the LDP must figure out how to reconstruct its power base. This task will not be easy since some of its traditional support groups have deserted the party, and its relationship with Komeito, a former coalition partner, has cooled.