SEOUL, Nov. 23 (Yonhap) -- Independent presidential candidate Ahn Cheol-soo on Friday announced his abrupt withdrawal from the presidential campaign, endorsing Rep. Moon Jae-in of the main opposition Democratic United Party (DUP) as the unified liberal candidate who will face off with ruling party hopeful Park Geun-hye in the Dec. 19 polls.
"I am giving up my presidential candidacy," Ahn said in a hurriedly arranged news conference in Seoul. "From now on, Moon Jae-in is the single liberal candidate."
The abrupt announcement came after the two candidates had failed to narrow differences on how to set the rules for merging candidacies.
"Locking horns over the method of merging candidacies is not righteous for the people anymore," a teary-eyed Ahn said, but added that he will "serve in a war as a commoner" to create "new politics."
"Although my dream for new politics will be delayed for a while, Ahn Cheol-soo is really longing for a new era and new politics," Ahn said.
Representatives of Moon and Ahn had made last-ditch efforts earlier in the day to finalize the format of a selection survey to field a single candidate, but no agreement was reached.
With four days to go until the agreed merger deadline, the election camp of Ahn on Thursday proposed a nationwide survey that would put equal weight on popular support for Ahn and Moon and an assessment of who is more likely to defeat conservative front-runner Park in the Dec. 19 election.
Ahn, a 50-year-old software mogul-turned-politician, and Moon, a former human rights lawyer who served as chief of staff to the late President Roh Moo-hyun, held one-on-one talks Thursday before coming up with their respective proposals, but failed to narrow their differences.
Ahn had argued the poll should ask respondents to choose which of them has a better chance against the 60-year-old Park, while Moon insisted on picking the better leader for the liberal camp.
Recent polls showed the former method gave Ahn the upper hand while the latter favored Moon.
In the event of a three-way race, the two liberals were widely expected to split the opposition vote and hand a victory to Park. As a daughter of the late authoritarian President Park Chung-hee, the ruling party candidate enjoys strong support from conservatives and the older generation.