Whether or not to introduce an open primary is becoming a key, and potentially divisive, issue in the ruling Saenuri Party’s race to nominate its candidate for the presidential election in December.

The undisputed frontrunner, Rep. Park Geun-hye, has reacted negatively to mounting calls from her challengers to allow any registered voter to vote in its primary, regardless of party affiliation.

Park’s competitors ― Gyeonggi Province Gov. Kim Moon-soo, former party leader Rep. Chung Mong-joon and senior lawmaker Lee Jae-oh ― see little prospect of winning the nomination under the current system adopted in 2005.

The nominee is supposed to be chosen by a combination of support from party delegates, rank-and-file members, registered voters and opinion polls. This system is thought to favor Park, who has tightened her grip on the party since she led it to win the parliamentary elections last month.

Figures close to Park have filled nearly all key party posts, with six of seven members on its decision-making Supreme Council supporting her.

Park, who recently resigned as head of an emergency council set up in December to overhaul the scandal-ridden ruling party, is expected to announce her second presidential bid next month.

The issue of changing the rules for the primary dominated a string of talks that Rep. Hwang Woo-yea, who was elected Saenuri chairman last week, held with Park’s competitors over the weekend.

The main argument for their case is that an open primary would enable the party to field a more competitive candidate in the presidential election by reflecting a wider spectrum of public support. It is also understandable for them to be concerned that the current system, susceptible to Park’s overwhelming influence, would not allow a fair contest.

Park rebuffed their arguments last month by saying, “Players should stick to the rules and it’s wrong to change the rules whenever requested by them.”

In her earlier remarks, she also expressed concerns about the possibility of an open primary allowing members and supporters of one party to vote for the weakest candidate from their opposing party, who could be more easily defeated in the presidential election.

From an objective point of view, it cannot be ruled out that an open primary might distort the result of a presidential nomination race, considering the political reality that rival parties have never hesitated to use such means to gain an upper hand. It may also cost a disproportionate amount and take too long to prepare in time for the nomination contest, which should be held by Aug. 21 at the latest under party regulations.

Judging from the current atmosphere, Park and her aides are unlikely to agree to changes to the current primary rules. It could not be said that Park is unfair and intransigent because she wants to keep them.

She accepted her defeat to Lee Myung-bak in a decent manner in the previous party nomination contest under the current scheme, which helped her lead among party members eclipsed by public support for Lee.

What might be worrisome for Park, however, as some of her aides admit, is the possibility of the lop-sided race dampening public interest and pushing her competitors to bolt from the party. Such a situation could be made worse by growing public excitement over the competition to grab the opposition’s presidential ticket.

Her final judgment on an open primary may later prove a crucial factor in her last bid to become the nation’s first female president in the footsteps of her father Park Chung-hee, who ruled the country for 18 years until being assassinated by his intelligence chief in 1979.