With Ms Park Geun Hye impeached and out of office, attention has shifted swiftly to South Korea's next presidential election, which must be held by May 9, and front runner Moon Jae In.
Mr Moon, a former human rights lawyer and chairman of the main opposition Democratic Party, is known for his liberal views and opposition to key decisions made by the conservative government.
In a statement yesterday, he welcomed the court's decision to uphold a parliamentary vote to impeach Ms Park and said that "South Korea will start anew".
Nevertheless, there is rising concern that if Mr Moon becomes president, he might upend all the deals that South Korea has struck with other countries, including the deployment of US anti-missile system Thaad (Terminal High Altitude Area Defence) and two landmark deals with Japan - on comfort women and intelligence sharing.
The 64-year-old has said he would reach out to North Korea's volatile leader Kim Jong Un for talks and also called for the reopening of the inter-Korean Kaesong Industrial Complex, signs that a Moon administration would pursue a North-friendly "Sunshine Policy".
Engagement with the North runs counter to the hardline policy maintained by the conservatives in the past decade. It also goes against efforts by the United Nations to toughen sanctions aimed at curbing Pyongyang's nuclear ambitions.
If Mr Moon gets tough on Japan, it would destroy the goodwill that the two sides have built and also their enhanced cooperation after the comfort women deal was inked in late 2015, under pressure from their common security ally, the United States.
Analysts say Mr Moon, a key aide to former president Roh Moo Hyun, may or may not follow through with his foreign policy views. Perhaps, like the late Mr Roh, Mr Moon will come to realise the importance of maintaining close ties with the US, said political scientist Kim Jae Chun of Sogang University.
"Roh had anti-American sentiments too, but after he became president, he realised there's no other way than to rely on the security alliance with America. Moon will also realise that the alliance is the cornerstone of South Korea's foreign policy and security," he added.
Mr Moon, who lost to Ms Park in the 2012 election, has been the most favoured presidential hopeful in the past few months.
The latest Realmeter survey shows that he has an approval rating of 36.1 per cent, more than 20 points ahead of his rivals - Acting President Hwang Kyo Ahn, Seongnam Mayor Lee Jae Myung and South Chungcheong Governor An Hee Jung.
Moon supporters are largely young liberals. He needs to win over older conservatives, who would baulk at his North-friendly stance.
Seoul National University's law professor Lee Jae Min said Mr Moon's popularity stems largely from public anger over Ms Park's scandal.
"Now that Park is gone, the real question for Moon is, is he ready to lead the country?"
