Breaking a postwar taboo, politicians started a full-scale parliamentary discussion Wednesday on whether to rewrite parts of the nation's hitherto untouchable Constitution. In the first session of an Upper House Constitution study panel, parties remained sharply divided over the premise of the panel debate. The two conservative parties -- the Liberal Party and the Liberal Democratic Party -- insisted that the panel discussions lay the groundwork for revising the Constitution, while the Japanese Communist Party and Social Democratic Party declared they will oppose any revision to the pacifist charter regardless of the course of panel discussions, which are scheduled to last for five years. The Democratic Party of Japan and New Komeito maintained they will only "discuss" the supreme code at this stage. "A series of educational and other problems have arisen as Japan has forgotten its historical and traditional values," Liberal Party member Sadao Hirano said. "And a large part of them are aftereffects of the Occupation policy. I call it (Japan's) Potsdam syndrome," he said, referring to the Potsdam Declaration that Japan accepted upon its surrender in 1945. Liberal Party member Chikage Oogi suggested that the panel invite the U.S. civil personnel who drafted the Constitution to appear before the Diet so the process of how it was born can be clarified. LDP member Takao Koyama said it is his understanding that the Constitution was made in violation of international law because Japan effectively did not have sovereignty when it was imposed in 1946. SDP and JCP members admitted there are conflicts between the Constitution and reality, but claimed that it is reality, not the Constitution, that needs to be adjusted. "This Constitution has effectively become Japan's identity. It should be heralded to the world as a Constitution that will shine in the 21st century," said Owaki Masako of the SDP. The widening gap between the Constitution and reality has been an impetus to establish the constitutional panels. One often-cited example is that while the Constitution prohibits private universities from receiving subsidies, the practice is carried out openly. The revisionist camp also claims that there are newly emerged concepts, such as environmental and privacy rights, which need to be stipulated in the supreme law. Although the panel has no authority to propose a constitutional revision, panel chief Masakuni Murakami, an LDP member, has said he personally hopes a new Constitution will be enacted in 2008. On Wednesday, Murakami proposed that panel sessions be held on weekends so the public can listen to the debate. The Lower House will hold its first meeting of the constitutional research panel today. A revision of the Constitution requires the approval of more than two-thirds of lawmakers in both Diet chambers, and from more than a half of the Japanese voters in a national plebiscite.