Democratic Party of Korea leadership candidate Jung Chung-rae (Yonhap) The ruling Democratic Party of Korea's leadership candidate, Rep. Jung Chung-rae, called Tuesday for a merger he said would be essential to strengthening the liberal bloc before the next major elections.Speaking at a meeting with party members in Sejong on Tuesday, the four-term lawmaker called for a merger between the Democratic Party and the Rebuilding Korea Party, a progressive party with ties to the ruling party."In the last presidential election, President Lee did not win more than 50 percent of the vote," Jung said. "We need to merge with the Rebuilding Korea Party as soon as possible, along with other progressive parties, to strengthen our political force and win in the next general election."Jung said such a merger will be a stepping stone to winning the general election and creating a one-on-one competition in the next presidential election.It is the second time Jung has raised the issue in as many days.At a party-member talk event on Monday in Cheongju, North Chungcheong Province, Jung said he had pushed for a merger with the Rebuilding Korea Party ahead of the June 3 local election, but failed."I pursued the merger, but it did not happen because someone opposed it," Jung said. "Had the parties merged, I think we would have won Seoul mayor."In the June 3 local election, Oh Se-hoon won a fifth term, defeating the Democratic Party candidate Chong Won-o by 1.15 percentage points. Jung also said that the election result in Pyeongtaek, Gyeonggi Province, would have been different had the merger taken place.While stressing the need for merging with the Rebuilding Korea Party, Jung also underscored unity among pan-liberal parties."We need to join hands with the Progressive Party, Justice Party, Social Democratic Party and Basic Income Party before the general election," he said.