The main opposition Democratic United Party’s senior adviser Lee Hae-chan is ready to run for the party’s chairmanship at next month’s national convention, according to officials Thursday.

The pro-Roh Moo-hyun politician, if elected, will work with floor leader Rep. Park Jie-won, who represents the former Democratic Party faction and the party’s stronghold in the southwest.

Interim chief Moon Sung-keun, another pro-Roh member, renounced his candidacy.

The former prime minister is seen as the frontrunner due to his political experience, public reputation and support from the party’s mainstream faction formerly loyal to the deceased president. He also promoted his in-party position by winning the parliamentary election in the administrative-hub city of Sejong.

Lee, however, faced internal backlash after he formed a cross-factional alliance with Park as many within the party accused them of political collusion for power sharing.

“Lee reviewed his candidacy plan from scratch in an aim not to cause factional friction but has found no other alternatives, especially considering the year-end presidential election,” said his aide Thursday.

“The official announcement will be made as early as this Sunday.”

The former prime minister also underlined his partnership with Rep. Park, hinting at his imminent challenge for the chairmanship.

“We must once again establish a democratic government, through the cooperation of the Kim Dae-jung group and the Roh Moo-hyun faction,” he said in a lecture in Chonnam National University on Thursday.

With Lee’s participation, the leadership competition is largely expected to be a four-way race.

Shin Geh-ryoon, lawmaker-elect in South Jeolla Province and former Uri Party member, is highly likely to announce his candidacy by the weekend, according to officials Thursday.

Shin represents the relatively neutral faction within the party and also maintains close ties with the pro-Roh group.

Seoul lawmaker-elect and former Culture Minister Kim Han-gill, too, has been showing signs of wanting to run for office, representing the non-Roh clique.

The two are expected to compete for the support of the party’s potential presidential candidate, especially Rep. Chung Sye-kyun.

The former chairman is counted as one of the party’s top candidates in the December race, together with Moon Jae-in, Reps. Sohn Hak-kyu and Chung Dong-young.

Former spokesperson Woo Sang-ho is also considered a significant candidate, representing the young reformers and labor activists within the party.

The new DUP chief is to play a crucial role in the lead up to the year-end presidential race. After a leadership vacuum, the chief faces challenges of uniting the divided factions and leading the party through the aftermath of the vote-rigging scandal of the minority left-wing Unified Progressive Party, with which the DUP is to form a political alliance by December.

By Bae Hyun-jung (tellme@heraldcorp.com)