"What's important is whether the president has sincerity in cooperating with opposition parties," he added.

Last month, rival parties accepted President Moon's proposal to form the consultative body in an effort to promote political cooperation.

Sohn, 71, has the task of bolstering internal solidarity following its crushing defeat in the June local elections and solidifying the party's status as the third-largest one.

Sohn's election, like that of Lee Hae-chan, new chief of the ruling Democratic Party, is another example of the return of political bigwigs to the political main stage, which some critics derisively call the comeback of "old boys."

"I think that the result reflects people's hope for stable reform at a time when local politics remain unstable," Sohn said, when asked what he thought about the criticism. (Yonhap)