The opposition as a whole has been thrust into crisis -- which is obviously a boon to President Moon Jae-in and the ruling party. If the situation continues, it would cost the country dearly.

One need look no further than the latest popularity ratings to see what the situation is. One recent public survey shows Moon’s approval rating running at 75 percent, and the support rating of the ruling Democratic Party of Korea at 53 percent.

The same survey put the support rating of the largest opposition Liberty Korea Party at 15.9 percent. The situation is not any better at other major opposition parties. The popularity of Bareun Party, which broke away from the Liberty Korea Party in the wake of former President Park Geun-hye’s corruption scandal, stands at 9 percent. The liberal opposition People’s Party registered an all-time low of 5 percent.

The situation gives Moon a free hand, as the liberal president is pushing for controversial appointments of senior officials despite ethical problems and a shift to disputed left-leaning policies like renunciation of nuclear power and the closure of elite high schools.

In some ways, the opposition parties have asked for the dismal situation they find themselves in. The crisis in the People’s Party is a case in point. Although the party lost the presidential election, it had been touted as a healthy liberal opposition, with 40 lawmakers, that could sway the business of the National Assembly where no party holds a majority.

Then a scandal about a fabricated tip-off left the party all but dead in one stroke. It indeed is shocking that the party’s allegation that President Moon’s son landed a job at a public agency with the help of his father was based on fabricated evidence.

It’s hard to fathom how a party could conduct a smear campaign against a major presidential candidate with false testimony from a man who presented himself as an acquaintance of the candidate’s son. It is also hard to believe that this was all done only by a rank-and-file member of the party, as it claims.

A bigger problem is that the party leaders -- former and incumbent alike -- have been busy avoiding and shifting responsibility. People who worked during the campaign with Lee You-mi, the party member charged with the manipulation of the testimony, have all denied involvement.

The party said its internal investigation also did not find the involvement of anyone higher up in the party hierarchy. The ongoing investigation by the state prosecution may shed some light on the case.

That does not spare people like former party leader Park Jie-won, who oversaw the election campaign, or presidential candidate Ahn Cheol-soo from responsibility for allegations that were made in the name of the party in the heat of the election campaign. Both insist they did not know the testimony had been fabricated.

Ahn has holed himself up in his apartment since the scandal broke. It would be strange if such irresponsible behavior by the leaders did not accelerate the fall of the party.

If the fall of the People’s Party was caused largely by a single scandal, the problems at the Liberty Korea Party are more complicated and structural.

Most of all, the party has yet to shake itself free from the legacy of former President Park Geun-hye, who sits in jail charged with corruption. It chose Hong Joon-pyo, who lost the snap election to Moon, as its new leader, but prospects for the party’s future are still dim.

One of Hong’s first tasks will be to reinvent the party and rebuild it as a bastion for conservatives by removing the vestiges of Park, whose loyalists still exert influence in the party. That effort should be coupled by endeavors to enlist respectable, capable outside figures.

The opposition’s foremost job is to keep the government in check. Neither the Liberty Korea Party nor the People’s Party can fulfill the mission without taking on painstaking reforms and restoring public confidence.