SOUTH Korea's President Chun Doo Hwan is a man on what looks like an increasingly slender balancing beam. On the one hand, opposition demonstrations against his authoritarian regime are mounting. Orthodox opposition leaders are apparently finding it difficult to stem the increasingly radical and anti-American character of some of the protests.
On the other hand, President Chun is under pressure from a tough and conservative military machine that has little patience with some opposition leaders, let alone the student radicals.
Says one perceptive observer close to the situation: ``The Army controls Korea. If Chun steps out of line, he could find himself locked up. You've got generals there who believe Kim Dae Jung [the principal opposition leader] is a traitor and should be dead.''
The Army is steeped in vigilance against, and suspicion of, communist North Korea. It has considerable justification, for North Korea is hardly your typical good neighbor.
In 1983, for instance, when most of the South Korean Cabinet was paying a friendly visit to Burma, the North Koreans tried to kill them all with a hidden bomb.
Seventeen South Korean officials were murdered, including the foreign minister.
The North Koreans only narrowly missed President Chun himself. This was the work of North Korean commandos, of whom there are many more, specially trained for behind-the-lines subversion.
Meanwhile, confronting South Korea's Army of some 540,000 men is a North Korean Army of about 700,000.
In armor and long-range artillery, the North Koreans have about a 2-to-1 advantage over South Korea, and all this manpower and weaponry is deployed very close to South Korea, along the demilitarized zone that divides the two countries.
Of course, there are American troops stationed in South Korea, designed to give the North Koreans pause -- and to underline the American defense commitment to South Korea.
North Korea has pursued an erratic and unpredictable course, and there are whispers from time to time of impending dialogue between North and South. Also, in contrast to South Korea's extraordinary economic growth, North Korea's economic stagnation may be causing it to grope for new economic solutions.
But the South Korean military remains understandably wary, and, with a real communist menace from the north, is hardly enthusiastic about turning over power in the south to an opposition that seems increasingly unable to control the radicals and revolutionaries.
But the more intransigent the military becomes, the more this is likely to fuel the radicals' cause.
This is the Catch-22 question confronting President Chun.
The path he has chosen in a country with little democratic background is one of gradualism. He says that by 1988 he will step down, but this transition will occur under a system that would probably permit the military to choose his successor.
The opposition is pressing for direct elections.
The Chun government has veered between crackdown and promised compromise, but orthodox opposition leaders are skeptical and the extremists in the opposition are impatient.
There is a chart for movement to democratic government in South Korea.
The key is timing.
The government's timetable is too leisurely for the opposition.
But if, as the military sees it, opposition demands get out of hand, the danger is that the Army would scrub even the intended transitional process and move South Korea back into martial rule.