South Korea: its politics travel two directions at once

''Excuse me, your dichotomy is showing,'' a political observer was heard to remark at a Seoul social event recently. The subject of their conversation and of the dichotomy was the current trend of South Korean politics.

Korea watchers have been weighing the apparently growing, government restraints against the also apparently growing muscle-flexing by the political parties, and trying to assess what, if anything, it all means for the long term.

Several recent events have been widely perceived as a distinct tightening of government controls, in spite of official protests to the contrary. A new ''resources management'' bill, which would give the government greater powers to prepare for emergency mobilization of the press, of key industries, and of some individuals (about 40,000), was seen by the opposition as a thinly-veiled device to extend government authority.

Equally alarming to many was the implementation for the first time ever of a law promulgated in the mid-1970s by the Park Chung-Hee regime, which makes it a crime for Koreans to insult the republic to foreigners.

The law was taken out of mothballs to sentence a human-rights activist to 18 months in prison. Kim Chul-Hi, who headed the ecumenical youth league of the Korean Council of Christian Churches, had distributed to domestic and foreign reporters a statement containing criticism of both the US and South Korean governments.

Then two American freelance journalists were given 10 days to leave the country. The order was later rescinded for CBS news correspondent, Anthony Barnes. But Nancy Langston, ABC correspondent, who contributed to other media (including The Christian Science Monitor), was forced to go. The official reason for her expulsion was that her visa was no longer valid. But Langston was convinced that the authorities were displeased with her reporting.

The other side of the picture shows the National Assembly, hitherto widely regarded as a rubber-stamp organization for government measures, demonstrating what one foreign correspondent, Mike Tharp of the Far Eastern Economic Review, described as ''the faint stirrings of participatory politics.''

In October, the main opposition parties, the Democratic Korea Party (DKP) and the Korean National Party (KNP) called for a ''new political climate.'' The DKP vice-president told parliament it was impossible for an opposition party to take power under the present election system and demanded an amendment in the basic press law ''to ensure freedom of the press as the first step towards political restoration.''

The opposition also raised doubts about the vague phrasing of the resources bill, and President Chun Doo Hwan's own Democratic Justice Party opposed another bill initiated by the Blue House (the president's residence) which eventually passed.

The National Assembly's independent attitude may be a sign that multi-party politics are emerging in South Korea - a necessary step for a peaceful and democratic transfer of power when Chun's seven-year term of office expires in 1988. Already observers are questioning whether Chun will really step down - the memory of former President Park, who promised the same but stayed on for 18 years, is still fresh. But Chun has always stressed his intention to quit after a single term, and there is no reason to doubt this so far. It has even been suggested that he won't be entirely sorry to relinquish the sometimes uncomfortably hot seat of power.