An LDP heavyweight who is throwing his support behind Prime Minister Junichiro Koizumi's re-election has an ulterior motive: the party regaining its majority in the House of Councilors.

By backing the prime minister, Mikio Aoki, who is secretary general of the party's Upper House caucus, has effectively split the votes of the LDP's largest faction.

Aoki is also a leader of the 42 Upper House members of the 100-member faction led by former Prime Minister Ryutaro Hashimoto.