While Prime Minister Junichiro Koizumi has enjoyed sky-high popularity ratings during his eight months in office, his main opponent, the Democratic Party of Japan, has moved deeper and deeper into trouble.

The largest opposition party finds itself in a quandary due to internal policy squabbles and the lack of a charismatic leader able to bring together members who hail from a wide political spectrum.

A Kyodo News poll released earlier this month showed the DPJ's support rate had dropped to 8.8 percent from 10.4 percent in September, the party's first dip below the 10 percent mark since the House of Councilors election in July.

In contrast, the approval rating for Koizumi remained at 79.5 percent, while that of his ruling Liberal Democratic Party was 46 percent.

"It appears to be an expression of the public's view that the DPJ is not united," DPJ leader Yukio Hatoyama said recently when asked about his party's sliding support ratings.

Critics say Hatoyama, a figure who has often been described as lacking charisma, is at least partly to blame for the disunity in a party that is a patchwork of forces with differing or conflicting creeds.

They say Hatoyama's strategy of backing the popular prime minister's reform programs as part of an effort to present the DPJ as an alternative to replace the LDP as a governing party did not work in the extraordinary Diet session that ended this month.

"If you tell the prime minister, 'banzai, you are the star of reforms,' you are not an opposition party, but (effectively become part of the) ruling party," Takahiro Yokomichi, a DPJ lawmaker who is the leader of the party's left-leaning members, said in an interview with Kyodo News.

"The public's expectations will focus on Prime Minister Koizumi, and any intention to vote for the DPJ will evaporate," he said, adding that Hatoyama, rather than praising Koizumi's reform plans, should be pointing out their shortcomings.

Another headache emerged for Hatoyama when a group of DPJ lawmakers defied his decision to approve the government's dispatch of Self-Defense Forces to the Indian Ocean to lend noncombat support to U.S.-led military operations in Afghanistan.

The lawmakers, including Yokomichi, voted against the dispatch in the Diet last month, despite repeated appeals and threats of punishment from the party leadership. Yokomichi, who was then vice president of the party, was later effectively stripped of his post.

Differences over security issues are nothing new in the party, since its legislators' backgrounds range from conservative former LDP members to left-leaning former members of the Social Democratic Party.

But the gap over policies appear to have become more conspicuous after the vote on the SDF dispatch.

Yokomichi, along with 33 other left-wing members in the party who voted against dispatching the SDF, formed an intraparty study group earlier this week, deepening the schism.

After the vote, conservative members who support Hatoyama, a former LDP lawmaker, compiled policy proposals that include plans on security and education that appear to be unacceptable to the left-leaning members of the party.

"We would be happy to see the former SDP members leave. This could be a good chance for them to do so," one member of the group said on condition of anonymity.

Another group of conservative DPJ lawmakers opposed to the policies of the former SDP members is also expected to set up a study group with like-minded members of the conservative opposition Liberal Party next month -- another move seen as symbolizing a growing rift within the party.

But Yokomichi says he has no plans to lead the left-leaning members out of the DPJ.

"Why should I leave the party I helped found? Those who want to join hands with the LDP should leave and join the LDP," said the former Hokkaido governor.

The DPJ could be headed for another round of internal bickering over security policy, since calls are growing in the LDP that the Diet should take up during its next regular session in January newly planned legislation for action in the event of a military crisis in Japan.

The differences over policy could even lead to a power struggle over the party's leadership.

A party presidential race is expected to be held in September, and speculation is rife that DPJ Secretary General Naoto Kan, who once headed the party, may be keen to take over Hatoyama's post.

Kan was touted as the darling of Japanese politics after playing a central role in uncovering the role of Health and Welfare Ministry officials in a scandal over HIV-tainted blood products when he served as health and welfare minister in 1996.

But he lost a party leadership race in September 1999 after his image as a clean and capable leader was damaged because of revelations of an extramarital affair. His lack of a strong foothold in the party also did not help in the election.

Some DPJ lawmakers say they fear that unless the party ceases its internal squabbles, it could be headed for even deeper trouble.

"We could be headed for a repetition of what happened to the now-defunct (opposition) Shinshinto" which dissolved in late 1997 after policy infighting, a DPJ legislator said. "We should keep in mind that our enemy is the LDP."