Seoul — The release from prison last week of South Korea's leading dissident, Kim Dae Jung, reflects the growing confidence of President Chun Doo Hwan in his government's ability to cope with the country's political and social problems.
The decision to transfer Kim from his prison cell to the hospital - and to allow him to travel to the United States for medical treatment - has officially been attributed to President Chun's ''personal humanitarian considerations.''
But a Korean civil servant who commented ''it will improve our country's image overseas,'' perhaps touched the heart of the matter. The government has stressed that the move was not influenced by any foreign pressure, but there is no doubt that the quiet diplomacy emanating from the United States Embassy in Seoul has been a factor.
Basically, the American argument was that the incarceration of Kim continued to provide a potential rallying point for local dissent and for criticism from abroad, which could undermine South Korean efforts to thwart communist North Korea in world forums. Privately, US diplomats have been telling members of government here that Kim Dae Jung does not have wide support among Korean Americans and would be unlikely to present a challenge to the regime from across the Pacific.
Since the move could not have been made without the full support of the most powerful arm of state, the Korean Army, it also makes it clear that the former contender for the presidency is considered effectively neutralized.
For many years, Kim with his liberal politics was a thorn in the side of Korea's 400 generals, and it was a military court that found him guilty of instigating the 1980 civilian rebellion in the southwestern provincial capital of Kwangju and sentenced him to death.
Another strong argument for Kim's release is the Japanese one. Japan still smarts about the kidnap of Kim by South Korean intelligence agents from a Tokyo hotel in 1973. With talks over Seoul's request for a $4 billion loan from Tokyo still at a delicate stage, Kim's release also may be interpreted as a conciliatory gesture to the new government of Yasuhiro Nakasone.
By personally commuting Kim's death sentence to a life term, later reducing that to 20 years and now freeing him, Chun has been able to play the highly visible role of ''angel of mercy.'' Some speculate that this latest move will clear the way for a future visit to South Korea by President Reagan.