The result of the Shizuoka gubernatorial election could be a bad omen for Prime Minister Taro Aso and the ruling coalition of the Liberal Democratic Party and Komeito. Mr. Heita Kawakatsu, 60, an economic history scholar, who was supported by the Democratic Party of Japan, the Social Democratic Party, and People's New Party, nosed out Ms. Yukiko Sakamoto, 60, backed by the ruling coalition.

Against the backdrop of the Shizuoka victory, if the DPJ has a strong showing against the the ruling coalition in the July 12 Tokyo Metropolitan Assembly election, the LDP could slip into chaos, followed by calls from within the party for Mr. Aso's resignation.

Mr. Kawakatsu defeated Ms. Sakamoto by a narrow margin (728,706 votes vs. 713,654). But it is a significant victory for the DPJ. It overcame a weakness it had from the start. Mr. Toru Unno, a former DPJ Upper House member, also ran, splitting the DPJ's support base. He got 332,952 votes. The DPJ managed to field Mr. Kawakatsu only about a month before election day.

While Ms. Sakamoto tried to dilute the fact that she was a candidate of the ruling coalition during the election campaign, Mr. Kawakatsu sold himself as a candidate supported by the DPJ. Amid high voter interest, voter turnout was 61.06 percent, 16.57 points higher than in the previous election. Mr. Kawakatsu will be the first Shizuoka governor from a non-LDP camp. It may be said that the DPJ's call for change of government helped build momentum in the gubernatorial election.

But the DPJ cannot afford optimism. A Kyodo News poll carried out on July 3 and 4 shows that the approval rating for Mr. Aso went up by 5.9 points from June to 23.4 percent. Asked what party they will vote for proportional representation in the coming general elections, 34.3 percent of the polled mentioned the DPJ, down 13.5 points, while 26.3 percent mentioned the LDP, up 7.6 points.

Irregularities over political donations involving DPJ leader Yukio Hatoyama's office are damaging the DPJ's standing. The fact that 78.3 percent of the polled are not satisfied with Mr. Hatoyama's explanation poses a serious problem for the party.