Tension is rising between the camps of the Democratic United Party’s Moon Jae-in and independent Ahn Cheol-soo over the possibility of the two candidates merging their campaigns.

While Ahn maintains an ambiguous stance on the issue having said only that a precondition is “true political reform,” with the public to judge when it has been achieved, the DUP is turning up the pressure on the former academic.

“The democratic progressive bloc will definitely put forward a single candidate for the presidential election. That candidate needs to belong to a political party. An independent president operating government affairs is impossible,” DUP chairman Lee Hae-chan wrote on his Twitter account on Tuesday.

From Ahn’s side the only comment with any semblance of detail so far has been from Yonsei University’s professor Kim Ho-ki, who is heading the camp’s political reform forum.

On Monday, Kim said that related discussions would begin in earnest in late October on a local radio station. However, Kim quickly issued a statement saying that the comment was only a personal opinion.

While the two sides vie for position, some say that a merger of Ahn and Moon’s campaigns is unlikely even through voters opposed to the ruling party want a united front.

“When the approval ratings are so close, candidates are likely to want to run until the end,” professor Shin Yul of Myongji University’s department of political science and diplomacy said. According to Gallup Korea, the gap between Ahn and Moon narrowed to 2 percent in the first week of October, which is within the margin of error.

Shin also said that a merger would bring a conflict of interest for the two candidates.

“The DUP can’t have their candidate support Ahn as that would mean that the party does not have a presidential candidate. For the party, having a candidate even if he loses gives it a reason to continue existing,” Shin said. He added that the DUP is increasing the pressure as it remains unclear whether or not Ahn is seriously considering merging his campaign with that of Moon.

“If Ahn was to support Moon, his conservative supporters who make up about 40 percent of his base would drop away. It is also impossible for Ahn to join the DUP as the main reason for his popularity is that he represents a breaking away from established politics.”

By Choi He-suk  (cheesuk@heraldcorp.com)