South Korea's promise to host advanced American missile defense technology on its soil may fall apart following President Park Geun-hye's de-facto resignation.
In July, Park's ruling Saenuri party agreed to host the Terminal High Altitude Area Defence system (THAAD), designed to shoot down ballistic missiles, as a counter to the growing sophistication of North Korea's weapons program.
Seoul and Pyongyang fought a three-year conflict that ended with a ceasefire in 1953. But North Korea issues frequent threats to its southern neighbor. In September, North Korea said it tested a miniaturized nuclear warhead that was reportedly the country's largest test to date.
Park's embrace of THAAD angered China and Russia, who contend its deployment on the Korean Peninsula threatens their respective national security interests.
South Korea's main opposition parties, the People's Party and Minjoo Party, are also opposed to THAAD, claiming that it won't effectively protect against the North, while seriously damaging relations with Beijing.
"The opposition has long believed that a confrontational stance toward the North is counterproductive, and needs to be balanced with greater engagement," explained Stephan Haggard, director of the Korea-Pacific program at the University of California San Diego.
The opposition's stance has some public support; the southern town of Seongju was chosen as the site for THAAD deployment but local citizens have rallied against the idea amid concerns about their homes becoming military targets.
Opposition politicians also don't wish to anger the world's second largest economy and Seoul's largest trading partner, Haggard added.
But with President Park now headed towards the exit door, the opposition has a chance of winning greater political control and that could threaten THAAD's future.
On Tuesday,Park announced she was relinquishing her powers amid her alleged involvement in an influence-peddling offense that sparked large-scale anti-government protests. Parliament, known as the National Assembly in South Korea, will now be deciding Park's fate, including whether she resigns before her original term ends in February 2018.
Presidential elections were originally slated for December 2017 but if parliament decides that Park's official resignation will take place in March or April, elections could be pushed forward to mid-year, Nomura said in a Tuesday note.
Park can't resign immediately as that would result in an election within the next 60 days, and neither the ruling nor opposition parties currently have strong candidates.