A new Constitution should be introduced in 2008, the head of the Upper House's constitutional research panel reiterated Tuesday. Masakuni Murakami, a senior member of the Liberal Democratic Party, told the Upper House plenary session that he aims to wrap up discussions by the panel by 2005 have the nation's hitherto untouchable supreme law revised in 2008. In a question-and-answer session, Murakami also urged, as a preparatory step toward revising the Constitution, that a new law stipulate procedures for holding a referendum. Any revision to the charter requires the consent of more than 50 percent of the voters in a national referendum. In the Upper House session, Murakami criticized Prime Minister Keizo Obuchi's "lack of enthusiasm" for constitutional debate in the Diet, saying the prime minister mentioned the issue "as if it were no business of his" during his policy speech Friday. Obuchi responded by saying that Murakami's proposal should be taken up by Diet panels. "I cordially hope for sincere discussions on the Constitution," he said, trying to rebuff the harsh remarks of his LDP comrade. Some 40 percent of the Upper House seats remained vacant in Tuesday's session, as the three major opposition parties continued their boycott of all Diet deliberations. Opposition lawmakers took to the streets of Tokyo in the afternoon to appeal to the public over what they call the strong-arm tactics of the LDP-led ruling bloc. Both Diet chambers formed a research panel in January to discuss revising the Constitution, the first time lawmakers have debated the charter in the legislature. The government had established a similar constitutional study panel within the Cabinet in 1957. On national security, Obuchi told the Upper House session that he considers the introduction of emergency defense legislation necessary to enable the Self-Defense Forces to protect the lives and properties of the people under the auspices of civilian control. Japan is the only major country whose defense authority is termed an "agency," Obuchi said, adding that he will gauge public opinion before proposing that it be changed to a "ministry."