South Korean President Park Geun-Hye speaks during an address to the nation, at the presidential Blue House in Seoul, South Korea, November 29, 2016. [Photo/Agencies]

The impeachment of Republic of Korea President Park Geun-hye on Friday marked a turning point in the country's politics and added yet more uncertainties to the geopolitical landscape of Northeast Asia.

Having lost her presidential powers and duties after members of ROK parliament voted overwhelmingly in favor of the impeachment, Park's political career is now in the hands of the Constitutional Court, which is expected to rule in about six months whether she must step down permanently.

There is no doubt that the ruling Saenuri Party (or New Frontier Party) and the main opposition Democratic Party of Korea will be locked in a bitter contest, more so if the court validates Park's impeachment making it mandatory for the next presidential election to be held within 60 days.

The simmering political tensions are not only about the fight against corruption but also about the continuing bipartisan clashes that have dealt a heavy blow to the approval rating of the Park administration. The overwhelming support for the impeachment also signals deep divisions within Park's Saenuri Party.

Yet there is no sign of a suitable candidate for the ROK's highest office, which Prime Minister Hwang Kyo-ahn is holding in the interim. UN Secretary-General Ban Ki-moon, who has shown interest in returning to ROK politics after his UN term ends at the end of this year, is a decent choice. But since the ongoing crisis has dealt a heavy blow to the Saenuri Party, opinion polls now favor the Democratic Party of Korea, whose political views are in stark contrast to the ruling party's.

If the opposition party wins the election, changes are likely in Seoul's foreign policy. To begin with, the deployment of the Terminal High Altitude Area Defense anti-missile system on the ROK soil may be stalled despite the United States' determination to proceed with the strategic plan.

The Park administration's decision to deploy THAAD was met with fierce opposition from the public and opposition parties in the ROK, as well as from China. That decision has in effect caused avoidable damage to Beijing-Seoul relations, warranting a proper revisit to the necessity of installing the anti-missile system.

Washington and Seoul should realize that THAAD cannot deter the Democratic People's Republic of Korea from pursuing its nuclear plan. Neither the shutdown of the Kaesong Industrial Complex, the last-remaining symbol of inter-Korean economic cooperation, nor multiple US-ROK joint drills succeeded in wearing the DPRK down. It is still bent on developing nuclear weapons. At least this fact should prompt the new ROK administration to reflect on its DPRK policy and soften its tone.

The military cooperation between Japan and the ROK, too, faces new challenges. Just last month, the two countries signed an agreement to share military intelligence, which was vehemently opposed by ROK people and opposition parties.

The security pact in the name of "better managing the threats" from Pyongyang, along with the possibility of Tokyo, too, seeking to install THAAD on Japanese soil, poses a strategic challenge to China. The Tokyo-Seoul security deal is not likely to be cancelled even if Park is ousted, but the new government could exercise extra caution in its implementation.

The author is an associate researcher at the Center for Northeast Asian Studies in Jilin province.