Four pillars support President Chiang Ching-kuo's rather benevolently authoritarian rule over Taiwan: * The Kuomintang or Chinese Nationalist Party.
* The intelligence and security forces.
* The military.
* The civil bureaucracy.
They overlap each other to some extent. But the only person who firmly controls every one of them is President Chiang.
His career has spanned periods of service with each of the four groups. And foreign observers rate him as more skilled in handling people, more flexible and supple in policy and administration, than was his father.
The first "pillar," the party, is the source of legitimacy both for President Chiang himself and for the government. The Kuomintang is the descendant of the Tungmenhui, the revolutionary party founded by Dr. Sun Yat-sen in 1905 to overthrow the Manchu dynasty.
Like his father, Chiang Kai-shek, President Chiang is chairman of the Kuomintang, which he has been trying to rejuvenate by opening up positions to younger, talented, island-born politicians.
Eleven different agencies make up the second "pillar" of power on Taiwan, the security and intelligence services. Their undisputed overall head is General Wang Sheng, director of the Defense Ministry's general political warfare department. The security network is the most important single element of power in Taiwan, and anyone who wishes to be ruler must control it.
The third "pillar," the military establishment, is grouped by some people with the security forces. But the two are separate, although some individuals have moved from one group to the other.
The fourth "pillar," the civil bureaucracy or technocrats who run the island's economy, is largely responsible for Taiwan's outstanding economic progress from the mid-1960s to the present. Premier Sun Yun-hsuan, an electrical engineer by background, is a leading representative of this group.
Besides controlling these four "pillars," President Chiang also is given credit for skillful management of the island's potentially most explosive issue -- the gap between native Taiwanese and mainlanders who fled to the idland after their defeat by the Communists.
Premier Sun told this correspondent in a recent interview that over a 30-year period mainlanders and islanders have come closer together in the knowledge that they face a common threat from the Communist mainland.
Concurring with the premier, some Taiwan-born officials say the gap between generations is greater than that between Taiwanese and mainlanders. Certainly there has been a degree of intermarriage between the two groups. Children of mainlanders speak Taiwanese and almost all Taiwanese speak kuo-yu (Mandarin), the official language of both Taiwan and Peking.
But there are after all only 2 or 2 1/2 million mainlanders out of a total population of nearly 18 million. Top posts in government still go mostly to mainlanders. In the armed forces, although the rank and file is overwhelmingly Taiwanese, the officer corps is mainlander-dominated and generals are almost all mainlanders.
Outside Taipei and the main cities, Taiwanese rather than Mandarin is the language mostly heard. President Chiang has worked to increase Taiwanese representation at all levels of government. His vice-president is Taiwanese, as is the governor of Taiwan.
But tensions between mainlanders and Taiwanese remain. The Kaohsiung incident a little over a year ago, in which over 100 dissidents were arrested, expressed these tensions. The Taiwan independence movement, active in the US though muted at home, keeps security services on the alert.
Of the four elements of power in Taiwan today, the technocrats seem the most open to the outside world, the most conscious of Taiwan's need for economic and democratic progress. This group has gone furthest in absorbing Taiwanese into its ranks.
No one knows who Mr. Chiang's successor will be. To be stable, however, it is certain that a post-Chiang government will require support from every one of the four groups so skillfully marshaled by the Pre sident.