Seoul — "Have you taught your children to swim?" Anywhere but in Seoul, the question is perfectly innocuous. Here, in a time of domestic stress, it has a grim meaning. Much of Seoul lies north of the wide Han River, just 26 miles down the Kaesong-Munsan corridor that is one of the two likeliest invasion routes from North Korea.
An outright invasion by North Korea seems unlikely. Still, one never knows. Most people in their 40s, and even in their late 30s, have memories of panic-stricken flights at the time of the 1950 invasion. There was only one bridge across the Han then. There are several today, but if they are all down, or if a route farther upstream seems safer, fathers are prepared to carry their tots on their backs or shoulders across the waters.
What, then, is North Korea capable of doing? Here is one possible scenario recently suggested by Lt. Gen. Chon Doo Hwan, military security commander widely regarded as the de facto ruler of south Korea:
North Korea could send hundreds of its troops to the South through tunnels dug under the demilitarized zone (DMZ) separating the countries. The troops, who would probably be disguised in south Korean Army uniforms, would sow confusion and terror among the civilian population.
No on really knows how many tunnels North Korea may have dug under the DMZ, but three have been discovered so far, General Chon said during a recent series of meetings with Korean publishers and editors. Who can say how many others may have been dug deep into the South Korean side of the DMZ, awaiting only a final explosion at some opportune moment? he asked.
General Chon spoke at a time when the Kwangju insurrection was still going on. Many in his audience resented his attempt to play on the nearly universal South Korean concern with security to justify the imposition of full martial law May 17, but no one could say for certain that General Chon's scenario was impossible. "That is our dilemma," said one who remembers Communist occupation and reoccupation of Seoul in 1950.
What can be said with reasonable certainty is that aside from its regular forces, North Korea has built up an impressive irregular or guerrilla warfare capability. United States military sources believe these irregular forces to number from 50,000 to 100,000 men in numerous independent units.
North Korea also has a fleet of AN-2 light planes capable of operating from rough airstrips and carrying 12 to 15 men. "It only takes 12 to 15 minutes from North Kaesong airfield to Seoul," General Chon said.
If there is an outbreak of urban disorder in South Korea, North Korea could conceivably try to take advantage of South Korean troop movements to send in its own forces, disguised, of course, as South Koreans.
Meanwhile North Korea's conventional forces are formidable enough. North Korea's ruler, Kim II Sung, has skillfully played off his two giant neighbors and allies, China and the Soviet Union, so that neither can afford to gainsay him for fear of leaving the field to the other. Ideologically, he seemed for many years closer to the Chinese, yet he has obtained from the Soviet Union not only arms more sophisticated than those of the Chinese, but also the capacity to build much of his defense equipment himself.
North Korea spends 15 percent of its gross national product on defense, compared to 6 percent by South Korea. Its ground combat forces number 600,000 to 700,000, compared to 600,000 in South Korea. It has 35 to 40 combat divisions: South Korea has 20. It has 2,500 medium tanks. (South Korea has only 840 tanks.) As Gen. John Wickham Jr., commander of US forces in Korea noted in congressional testimony this year, North Korea's Army is the fourth-largest among communist countries. "With approximately 4,000 artillery pieces, 2,500 tanks, 1,100 aircraft, and 450 ships, they have a significant numerical advantage over the combined forces that are in place defending the Republic of Korea. Except for sophisticated items such as aircraft, electronic equipment, and missiles, the North Koreans can produce virtually all of their military hardware, to include tanks and artillery."
The 39,000 US troops on the ground in Korea and US Air Force and naval units in and around the country help to redress the balance. Meanwhile North Korea's capacity to launch an invasion with little warning time continues to increase.