TOKYO, Sept 13, 2007 (AFP) - Shinzo Abe became Japanese prime minister a year ago vowing to build a "beautiful nation" but it was the familiar old problem of money scandals that precipitated his swift fall from grace.

The conservative 52-year-old, Japan's first premier born after World War II, pledged to restore the nation's pride and rewrite the US-imposed pacifist constitution.

But after less than a year he is calling it quits, wounded by a string of scandals linked to political funding that battered his popularity and made it almost impossible for him to push through his reform agenda.

While his predecessor Junichiro Koizumi was spared from major scandals during his more than five year reign, four of Abe's cabinet ministers quit, while another committed suicide amid a public funds scandal.

Analysts said that Abe's drive to build a more assertive Japan prouder of its identity also failed to resonate with many, though not all, voters.

"Abe was rare in a way that he tried to maneouvre the nation so strongly toward the more hawkish direction. But it was rejected," said Ikuo Kabashima, a professor at Tokyo University.

He said Abe's resignation was a setback to Japan's conservative political forces.

Abe took office in September last year on a mission to roll back the legacy of World War II defeat.

But polls showed that voters were more concerned about bread-and-butter issues such as pensions, and his party lost control of the upper house of parliament for the first time in its history in July.

"The governing party has now realised an agenda of rewriting the constitution and expanding Japan's military roles overseas would not make it win elections," Kabashima said.

The timing of Abe's announcement caused surprise as he had refused to quit after the July election drubbing and as recently as two days ago had vowed to stay in office.

Takehiko Yamamoto, a professor of political science at Waseda University, argued that Abe's resignation showed a lack of leadership and "immaturity as a political leader."

He said Abe called it quits before managing to put into place actual policies under his nationalist ideologies that he inherited from his grandfather, the former prime minister Nobusuke Kishi.

Kishi was a World War II cabinet member and was briefly jailed as a war criminal. Kishi later became a post-war prime minister and sought more a assertive style of diplomacy and a new constitution drawn up by Japan.

"Even after he reshuffled his cabinet, he was not in such a situation to carry out his doctrine," Yamamoto said.

Abe particularly struggled to persuade opposition leader Ichiro Ozawa to back an extension of a controversial mission in support of US-led forces in Afghanistan.

Yamamoto said whoever replaces Abe will likely have to compromise with opposition parties.

"Abe may hope for a scenario that his resignation will turn things around (for his party), but it would be extremely difficult when you look at the power balance in the upper house," he said.

Taro Aso, the LDP secretary general, who is seen as the front-runner to replace Abe, shares many of the outgoing premier's views.

But Yoshinobu Yamamoto, a professor at Aoyama Gakuin University, said that even Aso would probably need to take a slightly different tack to Abe.

"The direction to which Abe tried to lead the nation is not completely coming to a deadlock, but the conservative camp will have to stop for now and rebuild itself," he said.