The liberal opposition groups are set to select their joint candidate on Monday, stealing the show from their divided conservative adversaries. Through the selection process, they are consolidating their unity ahead of the Oct. 26 Seoul mayoral by-election.

But the ruling Grand National Party has yet to renew an alliance with its recently estranged supporters ― conservative civic groups and think tanks, which regard the party as ideologically tainted.

What happened last week determined where the two rival camps would be headed. On Wednesday, the main opposition Democratic Party, progressive civic groups and minor leftist political parties agreed on the rules by which to select their joint candidate.

But no such agreement was forthcoming from the conservative camp. Instead, Lee Seog-yeon, who represented the conservative civic groups and think tanks, declared on the same day that he would no longer pursue the mayoral post. He cited his low approval ratings in opinion polls as his main reason for giving up.

His decision was a setback to the ruling conservative party, which had wanted to get the most publicity out of a competition between Lee and its own nominee, Rep. Na Kyung-won.

Under the rules established by the opposition camp, an electoral college of 30,000 people is scheduled to vote for the selection of a mayoral candidate from among the three competitors on Monday ― Park Young-sun of the Democratic Party, Park Won-soon of the civic groups and Choi Kyu-yeop of the Democratic Labor Party. But it is essentially a race between the two Parks, with Choi having earned little name recognition.

To determine the winner, the outcome of the vote will be put together with the results of a TV debate held Friday and the opinion poll conducted on Saturday and Sunday. Pre-debate approval ratings were 49.9 percent for Park Won-soon, 42.9 percent for Park Young-sun and a mere 7.3 percent for Choi.

The nomination process is a boon to the opposition camp, given that it has been widely covered by the print and broadcasting media. For instance, the TV debate lasting one hour and a half was lively aired by three TV networks. The candidate selection on Monday will draw no less attention from the news media and the general public.

This event will upstage Na of the ruling party at a time when she badly needs to get her campaign message across to the electorate and boost her approval ratings. Barring the unexpected, however, she will be left out of the limelight until the opposition’s nomination process ends.

That should be a great loss to Na, who already trails Park Young-sun, not to mention Park Won-soon in opinion polls. According to a survey conducted last week, the approval ratings were 48.6 percent for Park Won-soon and 43.3 percent for Na on the one hand, and 46.7 percent for Park Young-sun and 44.7 percent for Na on the other.

Who should be held accountable? Na would be the last to bear responsibility, assuming she ever should. But Lee Seog-yeon, a former minister of government legislation, had his share of responsibility. Regardless of his initial low approval ratings, he should have fought Na for nomination until the last moment and, in the process, attempted to bring the civic groups and the party closer.

The primarily responsibility, however, should be borne by the Grand National Party, which has demonstrated very little in the way of firm determination to fight it out since Oh Se-hoon resigned as Seoul mayor, following a referendum against free school lunches rendered invalid by a turnout falling short of the statutory minimum in August.

Rep. Hong Joon-pyo, leader of the ruling party, once said the by-election was a local poll and, as such, must be primarily dealt with by the party’s Seoul chapter. He said the party headquarters would limit itself to a supporting role ― undoubtedly a ploy to avoid accountability should his party lose the mayoral race.

Moreover, even the supporting role he promised appears to be none of his concern, given that he is scheduled to embark on a five-day visit to the United States on Friday, despite him having no pressing job to do there.