If ill-conceived nominations cost the opposition alliance a majority in the parliamentary election, the election of candidates with moral or ethical deficiencies is threatening to hurt the ruling Saenuri Party.

When Kim Yong-min, a podcaster who gained fame for lampooning President Lee Myung-bak, was nominated by the opposition Democratic United Party, he was found to have made morally indefensible remarks, including those about Korean women forced into sexual slavery during World War II, on an Internet radio show. The opposition party should have withdrawn his nomination for damage control, but it did not.

The failure to act decisively against the podcaster turned moderates and swing voters against the opposition party, undoubtedly making it possible for the ruling party to win in many closely contested districts.

If it had not been for the podcaster’s nomination, the main opposition party could have won a majority of electoral districts, if not alone, in alliance with the small United Progressive Party. Instead, the DUP won 127 seats in the 300-member National Assembly, and the United Progressive Party took 13. On the other hand, the ruling Saenuri won 152 under the leadership of Rep. Park Geun-hye.

Holding herself responsible for the poor showing, Han Myeong-sook resigned as chairwoman of the DUP.

Now the ruling Saenuri Party is harried by a similar problem ― the election of two candidates with ethical flaws. It has forced both of them to quit only after much damage has already been done to the party.

During the run-up to the April 11 election, allegations of attempted rape and plagiarism were made against Kim Hyung-tae in a South Gyeongsang district and Moon Dae-sung in a Busan district, respectively. The party said that it would stand fast in its support for them until the allegations proved true.

The party’s decision was understandable, given that unfounded allegations had frequently been made against people seeking election to public office in the past. But a grave mistake the party made was that it did not move fast to take action when indisputable evidence was collected.

In the case involving Kim, his sister-in-law, who had claimed he attempted to rape her, later presented recorded remarks of his as evidence. Still, the party did not pay much attention. Was it because it wanted to keep its hard won majority intact?

But a change came when one news outlet after another began to take the scandal seriously. The party had been putting mounting pressure on its lawmaker-elect until he decided to leave the party on Wednesday.

Plagiarism allegations against Moon, an Olympic gold medalist in taekwondo-turned university professor, were easier to prove. All that was needed was to compare his dissertations with those from which he allegedly plagiarized.

It was found his dissertations contained not just simple usages of passages without proper attributions but “copy and paste” passages that kept the misspelled words found in the original. Still, the ruling party said it would delay making a decision on his case until the university that had awarded him a doctorate determined whether or not he committed plagiarism in his dissertation.

In an about-face several days ago, the party told Moon to leave. It did so when the news media started to turn up the heat on Moon as well as Kim. Moreover, public pressure was mounting on them to resign.

Moon was widely expected to announce his departure when he scheduled a news conference for Wednesday. But he canceled it and told reporters he would retain his party membership, compelling the party to set in motion the process of disciplining him.

The Olympic medalist announced his departure from the party on Friday following the university’s ruling that he plagiarized his doctoral thesis.

If the DUP wasted much of its political capital by dragging its feet on the case involving the podcaster, so did the Saenuri Party when it deferred decisions on its two errant lawmakers-elect. The blunder was a grave setback for Rep. Park of the ruling party, who apparently wanted to parlay her outstanding achievement in the parliamentary election to win the presidential election in December.