A statute is made invalid when six or more of the nine justices of the Constitutional Court decide that it is unconstitutional. But does it still have to require approval from six or more justices to invalidate a law when one justice post remains vacant?

This is not a hypothetical question. It is an actual question that was raised last Thursday when the National Assembly rejected a nominee by the main opposition Democratic United Party for the justice post that had remained unfilled since July 8.

For example, a law is ruled constitutional when a 5-to-3 decision is made in favor of its unconstitutionality though it could be invalidated if a nominee supporting the majority opinion were to be allowed to vote. As such, the court may delay an action on the constitutionality of a contested statue of great magnitude until the vacancy is filled.

For this reason, the president is required to appoint a new justice within 30 days when a justice retires or a vacancy occurs in other ways. But no appointment has been made for more than seven months because of wrangling between the main opposition party and the ruling Saenuri Party.

The National Assembly has the mandate to pick three nominees ― one recommended by the ruling party, one by the main opposition party and the remainder through bipartisan agreement ― for appointment by the president. The others are three appointed by the president and the remainder recommended by the chief justice for presidential appointment.

Trouble began to develop shortly after the Democratic United Party selected Cho Yong-hwan as a nominee in June. At a confirmation hearing, the Grand National Party, whose name was recently changed to the Saenuri Party, took issue with his remarks on the torpedoing of the South Korean corvette Cheonan in 2010. He said that he believed, as announced by the South Korean government, that North Korea was the culprit, but that he could not say so with certainty because he did not witness it.

These remarks by a nominee with a liberal reputation apparently jarred the conservative ruling party as they sounded sympathetic to North Korea. Even so, their decision to demand he be replaced was misguided, because it went against the long-established tradition of endorsing the opposition’s nominee unless he was unqualified as a court judge or found to lack moral character.

With the opposition party refusing to budge, the ruing party found it difficult to delay a vote on him any longer. At a meeting of lawmakers held prior to the ballot, the ruling party’s floor leader urged them to support the opposition party’s choice as they had traditionally done in the past.

But many refused to heed the request and voted against Cho. The tally showed that of the 252 lawmakers present, 115 voted in favor, 129 voted against and the rest abstained. After the vote, the opposition party accused the ruling party of vetoing him because of a difference in ideology.

The rebellion undoubtedly has serious repercussions. Among them is the vacancy that cannot be filled anytime soon. With the 18th National Assembly coming to an end, the process of selecting a new justice will have to start anew when the next parliament is fully organized in June. Here again, the opposition party, miffed by the ruling party’s veto, may not choose to speed up its process of selecting a new nominee. If so, the ruling party will be held accountable as well.

Another problem is that it may take a long time until bipartisan cooperation in choosing justices fully recovers. The possibility cannot be ruled out that the opposition party will choose to retaliate if it succeeds in putting the legislature under its control. Indeed, opinion polls show a landslide victory in the April general elections may not be beyond the opposition party’s reach.

This is not to say that the opposition party will be immune from public censure if it throws tantrums against the ruling party and obstructs the due selection process. After all, it has its share of responsibility because it failed to persuade its rival to endorse its choice.