On 8 April 1948, the U.S. Army ordered that a South Korean armed force be organized, equipped, and trained for internal defense and security. Fearful that the South Koreans might use the force to attack North Korea and embroil the United States in a war, Washington severely restricted the armament of the new army, depriving it of adequate antiaircraft, antitank, and artillery weaponry and denying it tanks altogether. On 5 December 1948, the South Korean government created the Ministry of National Defense as well as an army and navy. Simultaneously, all constabulary brigades were reclassified as army divisions. By March 1949, the South Korean security forces amounted to some 114,000 men, of which 65,000 were army, 4,000 coast guard, and 45,000 police. There was no air force. The South Korean Army had equipment for only 50,000 men, while approximately one-half of the police and coast guard were equipped with American carbines and side arms; the remainder used Japanese equipment of a similar type. On 1 July 1949, the United States organized the Korean Military Advisory Group (KMAG) to train and advise the South Korean Army.
By June 1950, when the Korean War began, the South Korean Army had grown to 98,000 men, but its equipment from the United States was sufficient for only 65,000. There were eight infantry divisions—the 1st, 2nd, 3rd, 5th, 6th, 7th, 8th, and Capital. Only one, the Capital Division, was near full strength; the others were handicapped because equipment for six divisions had to be allotted to eight. As for the navy, the South Korean Coast Guard had 6,145 men with an assortment of approximately ninety vessels, ranging from Japanese minesweepers to picket boats, of which less than half were operational. South Korea had practically no air force, because the United States was in no way committed to support one with advisors or materials. The air service numbered only 1,865 men, with fourteen aircraft that had been received in 1948 for liaison purposes only.
Thus, North Korea's armed forces were far superior in military strength when they invaded South Korea on 25 June 1950. Even though the South Korean army was only slightly smaller than the aggressors, the fighting capacity of the two forces was incomparable. The halfhearted U.S. support for South Korean forces was revealed in the failure of the army to defend itself successfully against North Korean aggression.
Badly outgunned at the outset of the Korean War and battered repeatedly by enemy offensives throughout, the South Korean military emerged as a significant force by the end of the conflict in 1953. As a result, the South Korean military establishment had a powerful voice in Korean domestic politics from the early 1960s to the early 1990s, mainly as a legacy of the Korean War. Indeed, the war turned the military into the most powerful organization in South Korean society.
During 1965–1973, the South Korean government authorized the dispatch of more than 47,000 South Korean troops to Vietnam at the request of the U.S. government. Because there was an annual rotation of troops, the total number of individual South Korean soldiers sent to Vietnam amounted to approximately 312,000. This was far and away the largest contingent of foreign troops sent to Vietnam outside of American forces. The United States provided offset payments for the Koreans in Vietnam, who gained valuable combat experience and also became proficient in the use of advanced U.S. weaponry.
By the end of the Cold War, although North Korea's weaponry was quantitatively far greater, it was also qualitatively inferior to that of South Korea, which was far more modern. With a 520,000-man ground force, South Korea maintains 1,566 tanks, 1,550 armored vehicles, 4,200 field artillery pieces, and 12 surface-to-surface missiles. The air forces of both Koreas were comparatively equal in quantity and quality. North Korea has more fighters and bombers, but its equipment was much older than that of the South Korean Air Force. South Korea's 40,000-man air force had 385 fighters, 51 special aircraft, 37 transport aircraft, 400 helicopters, and 263 other aircraft. South Korean fighters consisted mostly of F-5s and F-4s. But South Korea also had a number of F-16s, which have proven to be far better performers than North Korea's MiG-29s.
The navies of both Koreas have distinctively different characteristics. The South Korean Navy, consisting of 35,000 men, was centered on 49 destroyers and frigates, while the main component of the North Korean Navy of 40,000 men was 25 patrol submarines.
At the end of the Cold War, South Korea's most vulnerable spot was Seoul, the South Korean capital of more than 13 million people, that lies only 28 miles from the demilitarized zone (DMZ) line along the 38th Parallel. It is within easy range of North Korea's artillery. Estimates held that North Korea could rain 300,000–500,000 artillery rounds on Seoul in the first hours of a conflict, inflicting more than 1 million casualties.
Kwak, Tae-hwan, and Wayne Patterson. "The Security Relationship between Korea and the United States, 1960–1982." Pp. 83–97 in Korean-American Relations, 1866–1997, edited by Yuk-bok Lee and Wayne Patterson. Albany: State University of New York Press, 1999.; Lee, Kenneth B. Korea and East Asia: The Story of a Phoenix. Westport, CT: Praeger, 1997.; Republic of Korea Ministry of National Defense. "Defense Data and Statistics, 2001." Seoul: December 2001.