Policy of embracing rightist regimes in doubt

Events this week raised more doubts about the effectiveness of President Reagan's benign attitude toward client governments with poor records on human rights.

He calls his attitude ''constructive engagement.'' He has applied it to South Africa on the theory that the white government there would move faster toward extending equality to blacks if gently treated than if prodded. He has applied it to President Ferdinand Marcos in the Philippines on the theory that his military dictatorship is the only alternative to ''communism.''

This week the white government of South Africa sent members of the Defense Force into three black townships in the Johannesburg area - Sebokeng, Sharpeville, andBoipatong. Troops patrolled the streets while police searched houses. Hundreds were arrested.

This week a panel of five distinguished Philippine civilians handed to President Marcos two reports that unanimously placed on the armed forces the responsibility for the assassination a year ago of opposition political leader Benigno S. Aquino Jr. The chairwoman declined to put the ultimate blame on the Philippine armed forces chief of staff, Gen. Fabian Ver. The other four named him as the top figure in the plot.

Rioting has been frequent in the South African township of Sebokeng for two months. More than 80 blacks have been killed. Political critics of the government assert that a condition incipient of civil war now exists. Criticism has spread into the white community. Incidents of draft resistance have been reported. A formal draft resistance movement has been launched.

Regular army troops have been used before in riot control in South Africa, but this use seems to be on a larger scale and to be part of a long-term campaign aimed at suppression of black resistance.

Black unrest has risen following the recent extension of political participation to the Colored (mixed race) and Indian minorities in the population. The apartheid policy of the government is under heavier attack than before, both from the black majority and within the white minority.

The State Department in Washington meanwhile expressed the hope that President Marcos will bring to justice all those involved in the Aquino assassination ''no matter who they may be.''

The Reagan administration has not given up hope of salvaging the Marcos regime. One reason is doubt whether any successor regime would renew the American lease on the major US naval and air bases in the Philippines.

The naval base at Subic Bay and the air base at Clark field are the main forward bases for the American military position in Southeast Asia.

The question behind it all is whether US interests in the area are best served by continuing to support an increasingly unpopular regime. President Reagan asserted in his television debate last Sunday night with Walter Mondale that the alternative to the Marcos regime ''is a large communist movement to take over the Philippines.''

He conceded that ''things'' in the Philippines ''do not look good to us from the standpoint of democratic rights.'' But he could see no alternative except ''throwing them to the wolves and then facing a communist power in the Pacific.''

Have matters gone that far in the Philippines? Most observers, including the US State Department, think that a noncommunist alternative to the Marcos regime is still available and would be friendly to the US and its defense interests. Leaders of the domestic opposition contend that the longer the US continues to support the regime, the weaker will be the noncommunist alternative and the greater the possibility that the downfall of the Marcos family could lead to a communist victory.

History seems to indicate that timing is all-important in such matters. The record would seem to indicate that the US supported both the former Shah in Iran and former dictator Anastasio Somoza in Nicaragua beyond the point where a nonradical alternative existed.

But suppose that the Shah had been induced to liberalize his regime before pent-up opposition and dissatisfaction reached the boiling point?

And suppose General Somoza had been induced to dilute his dictatorship gradually and bring the more modern members of the emerging middle class into the government?

Any government which relies on military repression risks an ultimate and violent explosion which clears the way for the most radical reaction. The most stable modern governments are those which have long since learned to tolerate political evolution. Where the road to evolution is blocked by soldiers, revolution becomes the usual alternative.

No one can prove that the Shah might have saved his throne by allowing more freedoms. But it is a demonstrable fact that military repression of the opposition led in both Iran and Nicaragua to radical revolution.

This week the government in South Africa continued to move down the road of military repression. And this week the government in the Philippines faced a big decision.

Can it bring to trial and to justice its own top military leaders, or will it fall back on military repression to handle the rioting and civilian unrest that would certainly follow a failure to heed the advice from the State Department in Washington.