South Korea's opposition leader Lee Jae-myung called for swift action to stabilize the country following the impeachment of President Yoon Suk Yeol, urging cooperation between the government and parliament to address the crisis. Speaking on Sunday, a day after the opposition-controlled National Assembly impeached Yoon over his short-lived martial law decree, Lee proposed a special council to coordinate policy efforts between the government and legislature. He also urged the Constitutional Court to expedite its decision on whether to dismiss or reinstate Yoon, stating that a quick resolution would "minimize national confusion and the suffering of people." Yoon's presidential powers have been suspended, with Prime Minister Han Duck-soo now serving as acting president. If Yoon is removed, South Korea will hold a presidential election within 60 days. Lee, who leads the opposition Democratic Party and is seen as a frontrunner to succeed Yoon, said his party would not seek to impeach acting President Han. "The Democratic Party will actively cooperate with all parties to stabilize state affairs and restore international trust," Lee said, adding that he would work to resolve the crisis collaboratively. However, it remains unclear whether Lee's proposed council for government-parliament cooperation will materialize. Han expressed willingness to engage with the National Assembly but stopped short of endorsing Lee's suggestion. Meanwhile, Kweon Seong-dong, a leader of Yoon's People Power Party (PPP), dismissed the idea, stating that it was inappropriate for the opposition to act like the ruling party. The Democratic Party has already used its parliamentary majority to impeach Yoon's justice minister and the chief of the national police over the martial law decree. The party had previously considered impeaching Han but has now pledged to support his efforts to stabilize the government. Acting President Han has prioritized maintaining security and reassuring allies. He instructed the military to bolster its posture to deter provocations from North Korea and directed the foreign and finance ministries to minimize disruptions to South Korea's policies and economy. On Sunday, Han held a phone call with U.S. President Joe Biden, who reaffirmed the United States' "ironclad commitment" to South Korea and praised its democratic resilience. The leaders also discussed regional security concerns, including North Korea's nuclear program. Yoon's December 3 martial law decree, the first in over four decades, lasted only six hours but triggered widespread political upheaval. Yoon had deployed troops and police to block parliament from voting on the decree, which was ultimately overturned unanimously. Opposition parties accused him of rebellion, as martial law in South Korea is limited to wartime or emergencies and cannot suspend parliamentary operations. Law enforcement agencies are investigating Yoon and key officials involved in the martial law case, with allegations ranging from rebellion to constitutional violations. Yoon's defense minister, police chief, and two other senior figures have already been arrested. While Yoon is immune from most criminal charges as president, allegations of rebellion or treason fall outside that protection. Prosecutors have summoned him for questioning, but Yoon refused to appear on Sunday. Authorities plan to summon him again as part of their investigation. Lee has called for an independent investigation by a special prosecutor to expedite the probe, with the National Assembly passing legislation last week to authorize such an inquiry. Observers note that the Constitutional Court could issue its ruling on Yoon's impeachment more quickly than its 180-day deadline, based on past cases. In 2004, the court reinstated President Roh Moo-hyun after 63 days, while in 2016, it dismissed President Park Geun-hye after 91 days. Meanwhile, Yoon remains defiant, denying accusations of rebellion and criticizing the Democratic Party as an "anti-state force." He has vowed to "fight to the end" to defend his actions, framing his deployment of troops as a warning against parliamentary overreach. — Agencies