Last June, Rep. Lim Su-kyung of the main opposition New Politics Alliance for Democracy was at the centre of a sour ideological debate after calling North Korean defectors "apostates."
A former high-profile pro-unification activist, Lim was once called the "flower of reunification" by Pyongyang for her unauthorized participation in the 1989 World Festival of Youth and Students in Pyongyang as a university student.
The 44-year-old lawmaker made the remarks during an impromptu meeting with a defector-turned-college student at a bar, who then revealed the incident on his Facebook account
The incident came at a delicate time when leftist politicians are being criticised anew for their past pro-North Korea activities. The National Assembly has since been working to oust Lee Seok-gi of the United Progressive Party, who was convicted of conspiring to overthrow the government.
The beleaguered politicians were called "jusapa," a term used to describe student activists in the 1980-90s who espoused the ideology of "juche," or self-reliance, which is the theoretical foundation of the North.
Six decades after the Korean War, controversy persists over jusapa or pro-North forces, with their definition and members remaining unclear. Conservative administrations and politicians have often triggered the ideological dispute in the run-up to key elections, which critics said was an attempt to agitate public sentiment and sway the vote for the sake of national security.
This represents a painful legacy of the divided peninsula: North Korea has since its birth been a major source of not only security threats but also a deep-rooted ideological rift in South Korean society.
Lee, president of the Korea University student council in 1996, was a jusapa factionist until 1999, when he converted after two years in prison.
He and his party colleague Rep. Kim Jae-yeon bore the brunt of conservative attacks for their involvement in pro-North groups during their activist days in the 1990s. In 2003, Lee was sentenced to 2 1/2 years in prison on charges of violating the anti-communist National Security Law.
The juche idea, the original political theory of the Kim Il-sung regime, teaches that man is the centre of everything and thus decides his own fate. It has become more elaborate since 1955, resulting in a set of principles that define the North Korean leadership and their policies.
In the 1980s, the student movement diverged into two factions called the NL (National Liberation) and PD (People's Democracy). Jusapa was a pro-North Korean element of the NL, and its most powerful sub-group.
The NL believed that various problems in South Korean society derived from the division of Korea due to the influence of an external force: the US They believed Washington must step out of the picture for the two Koreas to reunify. Its former members remain the fiercest opponents of the US Forces Korea and the Korea-US Free Trade Agreement.
The PD faction emphasised Marxism-Leninism, focusing on class conflict and seeking to overthrow the dictatorship through a popular revolution. It is not necessarily pro-North or anti-US, but rather concentrates on subverting the capitalist system and promoting the interests of the proletariat.
In the wake of Kim Il-sung's death in 1994, many student activists were disenchanted with the North's totalitarian regime and dissolved the underground party. Its existence came to light in 1999 when Seoul's intelligence agency arrested a group of those who refused to convert and attempted to rebuild their forces.