Defying earlier predictions, the ruling Saenuri Party won a majority in the parliamentary elections on Wednesday and put the National Assembly under its control again. Due credit must be given to Rep. Park Geun-hye, who reorganized a party in disarray after the October by-elections and successfully rallied conservative voters behind the party.

It was not just pre-election opinion polls but exit polls that indicated that the opposition alliance could beat the ruling party. They did not even rule out the possibility that the main opposition Democratic United Party would control the 300-seat National Assembly alone.

But the predictions proved wrong. The Saenuri Party gained 152 seats, including 25 on proportional representation, followed by the Democratic United Party with 127 and the main opposition party’s ally, the United Progressive Party, with 13. The remainder went to a smaller party and independents.

A detailed analysis of voter behavior by age, region and other factors will be needed to determine what exactly produced this electoral outcome. Still, a fairly reasonable and informed guess is not out of the question.

One defining feature of the electoral strategy pursued by Park was for the Saenuri Party to distance itself from President Lee Myung-bak’s administration, whose alleged misrule the opposition alliance targeted for an attack. Park, who has set her sights on the next presidency, focused on building a party with a brighter future under her leadership.

More importantly, she appealed to conservative voters to help check the looming upsurge of the opposition, which moved further away from the center when the center-left Democratic United Party allied itself with the far-left United Progressive Party. Her call for a check on a resurgent opposition alliance apparently worked on moderate conservatives and independents, who had considered supporting the main opposition party to bring about change but changed their minds in the face of what they regarded as an alarming tilt toward the far left.

For the opposition alliance, high approval ratings in pre-election opinion polls proved to be a bane in disguise, which fueled arrogance among its leaders and candidates and led them to make ill-advised decisions. One such case involved a podcaster, who gained fame by making vitriolic comments on unlawful or morally indefensible acts allegedly committed by the Lee administration and ruling party figures.

Pressure mounted on the Democratic United Party to withdraw his nomination when he was found to have made sexually abusive and other irresponsible remarks years ago. He should have resigned to limit damage to the party, but he did not. Nor did the party withdraw his candidacy, ignoring the souring public opinion.

Moreover, the opposition alliance’s diehard opposition to the Korea-U.S. free trade agreement undoubtedly turned many independent and moderate liberal voters against its candidates. Its demand that the agreement be abolished if it is not amended in the way it finds fit must have sounded absurd to the voters, given that negotiations on the accord were initiated by the previous liberal administration.

For her misjudgment, Han Myeong-sook, the main opposition party’s leader, will have to hold herself responsible. The party under her leadership squandered a rare opportunity to put the ruling party and its administration under check. By doing so, it will have to fight a steep uphill battle when the presidential election comes around in December.