The leader of the Korea Confederation of Trade Unions said on Tuesday it is impossible for the group to continue to support the scandal-ridden Unified Progressive Party.

The umbrella trade union group is the largest supporter for the leftist minority party.

“We have allied together in every election, but it is impossible for us to support the UPP in its current shape,” KCTU chairman Kim Young-hoon said in a radio interview.

The labor group plans to finalize its stance at its central committee meeting Thursday.

Some in the group even proposed that its members quit the party en masse.

“We are to decide whether to dump the party completely and start out with a new party, or play a leading role in reforming the UPP by stepping in all-out,” he said.

The KCTU’s disapproval will be a fatal blow to the party’s mainstream group, whose suspected election fraud and refusal to resign from the leadership drove the party into a crisis.

Kim remained skeptical of the prospect of the union group’s collective defection.

“Strictly speaking, withdraw of support is one thing and departure from the party is another. They are very grave matters and should be considered in different lights,” he said.

Defection en masse may infringe on the political freedom of individual union members, he added.

Earlier in the day, Kang Ki-kab, elected Monday chief of its emergency panel, pledged to punish those responsible for violent disruptions of an in-house voting over the weekend to determine the fate of the embattled leadership and elected party-list members.

“We will conduct a thorough investigation and impose severe penalties on those who used violence during the committee meeting,”he said.

The central committee meeting on Saturday was interrupted by violent hardline mainstreamers, causing the vote to be conducted online the following day. A majority approved a reform proposal that a new leadership panel be set up and the problematic lawmakers-elect withdraw from the party list.

Rival factions continued to wrangle over the legitimacy of the vote. The mainstreamers claimed that the online vote violated the rule of democracy and threatened to file for an injunction to invalidate the results.

Kang rebuffed their claim.

“The online vote was based on the party constitution and even former co-chair Lee Jung-hee acknowledged the legitimacy of the system in the past,” Kang said.

He also demanded that the disputed lawmakers-elect comply with the committee decision and step down.

However, the two most controversial figures, Lee Seog-gi and Kim Jae-yeon, have already registered as lawmakers, according to the National Assembly on Tuesday. It is now almost impossible for the party to strike them off the list.

Once a parliamentary term begins, a lawmaker may not be dismissed unless two-thirds or more of the entire house vote in consent.

By Bae Hyun-jung (tellme@heraldcorp.com)