Rep. Park Geun-hye was nominated as presidential candidate of the ruling Saenuri Party at its national convention Monday, entering the main stretch of her second, and probably last, bid for the post held by her father for 18 years until his assassination in 1979. If she wins the election on Dec. 19, she will become the nation’s first female president.

Park beat her four rival contenders by a wide margin in the nomination vote, which combined ballots cast by party members and selected citizens with the outcome of a public opinion poll.

Her dominant status in the party, which she led to an unexpected win in the April parliamentary elections as its interim leader, does not guarantee her presidential victory against a liberal rival candidate who has yet to emerge. The main opposition Democratic United Party is to kick off its primary race this weekend and pick its nominee in late September. Whoever is selected as DUP nominee is expected to seek to unify the liberal camp’s presidential candidacy with software mogul-turned-professor Ahn Cheol-soo, posing a challenge that some political observers say might prove insurmountable for Park.

A poll last week placed Ahn with 49.2 percent ahead of Park at 44.1 percent in a hypothetical presidential election matchup. Park led Rep. Moon Jae-in, the frontrunner in the DUP race, by a small margin of 4.5 percent.

Her vulnerable position against Ahn, who is popular with young voters due to his clean image, interest in helping the less privileged and emphasis on common sense, indicates she still has many obstacles to overcome to reach her final political goal.

In a bid to enhance her chance of winning the December vote, Park has shifted her conservative party to the center and, in some issues, closer to the left.

She has tried to win voters’ hearts with policies to expand welfare programs, create more jobs and tighten the reins on big companies. She has also suggested taking more conciliatory approaches toward North Korea than President Lee Myung-bak, who has adhered to rigid principles of reciprocity.

Such positions depart from her focus on economic growth, social order and security during her previous presidential campaign in 2007, when she lost the nomination of the Grand National Party, the predecessor of the Saenuri Party, to Lee.

She still has to shed her unaccommodating and incommunicative image and salvage her reputation for reforming the ruling party amid allegations that a Saenuri lawmaker won proportional representative candidacy after giving money to one of her close aides before the April elections.

Park expressed her determination to address the matters by pledging efforts toward political reform, elimination of corruption and integration of society in her acceptance speech.

Her fundamental task, however, may be how to overcome the legacy of her late father, Park Chung-hee, who put the country under his authoritarian rule while driving the economic growth. What her father did ― laying the groundwork for the nation’s current prosperity and setting back democracy ― remains a double-edged sword for her campaign. Park has been cornered into expressing her view on the May 16, 1961 military coup that took her father to power.

With little differences in policies between the rival camps, the opposition is expected to attempt to cast Park as the daughter of an authoritarian ruler and frame the election as a choice between the past and the future. It may serve her better to draw a clearer line between her father’s merits and mistakes, a work difficult for a daughter but necessary for a national leader.

Park’s election fate will hinge particularly on how successful she will be in winning over young and independent voters. It will be made possible when she can decouple herself from the negative past and establish herself as a future-oriented leader capable of solving problems the nation faces.