South Korea is not the Philippines. It's making real economic and social progress. It's got a proven, menacing foreign foe. Its government's legitimacy is not being challenged in the streets. Still, there are some catchy echoes. The opposition is rumbling, and the government is responding sternly. There is, too, a pattern in Korea of looking to the Philippines and to the American reaction to events there. Less than a month after Ferdinand Marcos declared martial law in Manila in 1972, Park Chung Hee, observing that the Americans had swallowed it, did the same in Seoul. Now, with unrest mounting in the Philippines, both government and opposition appear to be acting with that in mind.

Korea enjoyed a vigorous political life in the early 1970s. It was too vigorous for its president (former general) Park, who, having narrowly defeated Kim Dae Jung in 1971, moved to take the chance out of politics by installing military rule. Under the system as now practiced, the next president will be elected indirectly by an electoral college. The opposition fears this gives the current president, former general Chun Doo Hwan, a lock on picking his successor. It has been trying to organize a petition drive to bring about direct popular election instead. As a result, former candidate Kim and fellow opposition leader Kim Young Sam, both potential presidential candidates in 1988, are under house arrest.

There is no sense of crisis in Korea, and in Washington there is a deep aversion to seeing one develop in a second American dependency in Asia. President Chun and the generals are old hands at containing political agitation, and the Kims are old hands at enduring house arrest and worse. Perhaps not much more will happen.

It would be prudent, however, not to count on it. The dere for democracy is real in Korea, as befits a society of growing economic and political sophistication. The generals and the Kims understand that in Korea as in the Philippines the United States conducts an uneasy double patronage -- of security as well as of democracy. Each group is alert to ways to draw American policy to its side. In the Philippines the United States is moving, if hesitantly, toward the position that democracy is the best guarantee of security. The position is no less relevant in Korea.

President Chun insisted to Washington Post interviewers just a few weeks ago that he does not obstruct or harass his political opposition. Then what are they doing under house arrest? Is President Chun's word good?