Shigeru Ishiba, the former prime minister, left the chamber before a vote on a bill to cut the consumption tax on food and drink, which passed the House of Representatives on the 6th, without indicating whether he supported it. A former prime minister voting against his own party's line is unusual, but there is precedent.
After the vote, Ishiba told reporters the funding was unclear and that the bill would damage the public finances. "I cannot dispel my concerns," he said.
Three other Liberal Democratic Party lawmakers also left before the vote: former election strategy chief Yuko Obuchi, former justice minister Yoshihisa Furukawa, and former Economic Planning Agency director-general Hajime Funada.
Koizumi skipped a vote and faced no penalty
In March 2009, former prime minister Junichiro Koizumi was absent from a second vote in the lower house on a supplementary budget bill for fiscal 2008 that secured funding for the fixed-amount cash handout program. He had argued in advance that it was not a bill that had to be passed by using the two-thirds override, and on the day he submitted a notice of absence "for personal reasons" to the LDP's parliamentary affairs committee.
The party declined to discipline him. Then-secretary-general Hiroyuki Hosoda said Koizumi had filed a notice of absence and had a record of achievement as party president, and made clear no penalty would follow. Jiro Ono, a lower house member who left during the vote, was given a formal reprimand.
Hatoyama voted no and was suspended
In June 2012, former prime minister Yukio Hatoyama voted against a bill to raise the consumption tax pushed by the Democratic Party of Japan government of Yoshihiko Noda, defying the party line. It was a large-scale revolt: 57 DPJ lawmakers including former leader Ichiro Ozawa voted no, and 15 abstained.
After the vote, Hatoyama ruled out leaving the party. "I want to turn it back into a group that stays inside the party and fights properly for the people," he told reporters. Ozawa and others quit and formed the new party Kokumin no Seikatsu ga Daiichi. The DPJ suspended Hatoyama's party membership for three months.
Ishiba has said of his own position, "Let's do this together."