It has been confirmed again that factions of the United Progressive Party rigged the vote for the selection of parliamentary nominees for proportional representation in the 19th National Assembly. But the faction that had the party under its control and managed the vote refuses to accept these findings by the party’s ad hoc investigation committee.

The committee, which said in its first report in May that the pre-April 11 election vote by party members had been fraudulently conducted, reaffirmed its earlier findings on Tuesday. It said fraud was extensive in the vote ― from vote management to balloting online and at the polls.

In the online ballot, which accounted for 85 percent of the vote, the committee said, the faction cast proxy ballots for its members on the list of proportional representation ― Lee Seok-gi and Kim Jae-yeon. It said the faction also conducted multiple voting and had unauthorized access to the party’s server when the online voting was being carried out.

A case involving Kim, who was at the top of the proportional representation list, was an example showing how serious the vote-rigging was. Of the ballots cast for Kim at the polls, the committee said, 32.4 percent of the total were invalid because they were either multiple or proxy.

This finding alone confirmed why Lee is not qualified to retain his position as a lawmaker. He should resign, together with Lee.

But the faction brushed the findings aside, claiming that the second report on the fraudulent vote was unsubstantiated as the first one was. It also said Kim and Lee will not resign as lawmakers. Now the progressive party will have to take the process of withdrawing membership from the defiant lawmakers and others involved in the fraud.

Kim and Lee should be reminded that the vote-rigging is a matter of great concern to the public, given that their party is a public institution subsidized by the government. The offense cannot be a case that matters to the progressive party alone.

What needs to be done under these circumstances is for the prosecutors’ office to speed up its investigation into the case and take legal action against those involved in the scam. If the two lawmakers continue to refuse to resign on their own, the ruling Saenuri Party and the main opposition Democratic United Party will have to take the process of forcing them out sooner or later.