The Democratic Party of Japan decided Friday to suspend the party membership of former Prime Minister Naoto Kan for three months as he supported an independent candidate in Sunday's upper house election in defiance of a decision by the main opposition party.
DPJ President Banri Kaieda proposed the step at a meeting of the party's executive board, which immediately approved it, party lawmakers said. Kaieda had initially proposed earlier this week expelling the former leader from the party.
The DPJ suffered a major setback in the House of Councillors election, in which Prime Minister Shinzo Abe's ruling bloc wrested control of the chamber from opposition parties.
Kan supported a candidate who had lost the party's endorsement in the Tokyo constituency. The DPJ had initially planned to field two candidates in the capital but revoked its backing of one of them only two days before official campaigning started, in view of the slim chance of securing two seats there.
Neither candidate was elected, due apparently to a split in the DPJ's vote amid the confusion.
Kan apologized to the party when the executive board met Wednesday. Some of its members then voiced reluctance to expel Kan, saying the punishment would be "too severe," and the board instead opted to suspend his membership, the lawmakers said.