Two recent moves by judiciary and law-enforcement authorities are a grave warning against the Liberal Democratic Party's pork-barrel politics. One is the Supreme Court rejection of an appeal by former Construction Minister Kishiro Nakamura against a Tokyo High Court ruling that found him guilty of taking a bribe from a construction company. He is to serve 18 months in jail and pay 10 million yen in fines. It is the first time that a Diet member has received a final conviction under a law that bans the taking of bribes through political mediation.

The other move is the arrest of two members of the LDP's Nagasaki prefectural chapter by public prosecutors on charges of receiving illegal donations from local public works contractors in connection with a Nagasaki gubernatorial election. One of the two men is the chapter's former secretary general; the other is director of its secretariat.

Both cases are a fresh reminder of the sordid money ties that bind public works contractors and influential politicians.

In the Nakamura case, the former LDP legislator received a request from a major construction company in 1992 to stop the Fair Trade Commission from bringing charges against a consortium of 66 construction firms involved in public works. At the time the FTC was investigating them on suspicion of bid-rigging. According to investigators, Nakamura successfully pressured the FTC chairman and took 10 million yen in bribes as a reward for his role.

The Supreme Court concluded that Nakamura had used his influence to prevent the FTC from filing charges against the group of builders and from investigating suspected bid collusion among its members. In doing so, the court expanded the scope of application of the law that prohibits politicians from taking bribes through mediation. This is the new legal significance of Nakakuma's conviction.

The Nakamura case, which came to light in the early 1990s when the LDP's decades-long monopoly on power was coming to an end, is known as the " 'zenekon' bribery case" (zenekon is Japanese shorthand for "general construction contractors"). It has been regarded as a typical example of the collusion between pork-barrel politicians and industry groups.

Around the same time, in March 1993, former LDP Vice President Shin Kanemaru was arrested by Tokyo prosecutors on charges of massive tax evasion. In the course of investigations it was revealed that not only Diet members but also local government chiefs had received bribes from various zenekon. In the same year, the mayor of Sendai and the governors of Ibaraki and Miyagi prefectures were arrested. Nakamura was arrested in March 1994, one year after Kanemaru.

In 1993, in a surprise move that would change the nation's political landscape, a no-confidence motion against the Cabinet was passed with the support of LDP dissidents, leading to the dissolution of the Lower House. In the snap general election that followed, the LDP suffered a crushing defeat that forced Prime Minister Kiichi Miyazawa to resign, ending the 38-year streak of one-party LDP rule. With the party in opposition for the first time, the so-called 1955 regime -- which had polarized the political world between the LDP and the Japan Socialist Party since 1955 -- collapsed.

The political situation subsequently became extremely unstable as one coalition government after another came into being. The 1990s was a "lost decade" for Japanese politics as it was for the Japanese economy, which plunged into recession at the beginning of the decade following the collapse of the asset-price bubble.

With political parties mired in recurring money scandals, more than 10 legislators were indicted on corruption charges even after the Kanemaru case closed. And as recently as last year, Lower House member Muneo Suzuki, former state minister in charge of Okinawa and Hokkaido development, was arrested and indicted for receiving a 5 million yen bribe from a logging company in return for his intercession with officials of the Forestry Agency.

Nakamura, who once served as an aide to former Prime Minister Noboru Takeshita as well as Kanemaru, climbed the political ladder so rapidly that he was regarded as a future candidate to lead the Hashimoto faction, an offshoot from the Takeshita faction. Suzuki was also a member of the Hashimoto group.

It is disturbing that dirty pork-barrel politicians have been regarded as future leaders of Japanese politics. This shows that the LDP is structurally corrupt.

The Nagasaki case cannot be brushed aside as a local political scandal. Two key members of the chapter are charged with requesting campaign money from a public works contractor and receiving millions of yen in illegal donations from the firm immediately before the gubernatorial election of last February.

The Public Offices Election Law prohibits politicians from requesting or receiving campaign donations from companies that have contracts with the central government or local administrations.

Public works spending in the fiscal 2003 government budget has been cut by 3.9 percent from the year before, reflecting tight fiscal conditions. But the relationship between builders vying for a shrinking public works pie and politicians trying to collect funds and votes through intercession remains unchanged. Indeed, national politics is built on corrupt local politics, as exemplified by the Nakagaski case.

Last March, Prime Minister Junichiro Koizumi ordered party executives to study ways of expanding the ban on donations from public works contractors on a routine basis, not just in the campaign period. However, his order has been virtually ignored. To promote political reform, legislation banning donations in principle should be established. The Diet has its work cut out.