US worries about rightist trend in Salvador election

United States hopes for a moderate, reformist, and democratic outcome to El Salvador's election process may have suffered a major setback.

As five right-wing parties in last Sunday's balloting tentatively form the apparatus for what they term ''a government of national unity,'' Washington's role here and throughout Central America could be complicated immensely. A reassessment of US policies may be necessary.

If this rightist coalition holds together, the US is going to have to decide whether to embrace--and continue financial support to--a government that is less reformist than the Reagan administration wanted.

Many of the reforms instituted by the joint military-civilian junta nominally headed for the past two years by President Jose Napoleon Duarte could be reversed. At best, they are likely to be halted or watered down.

The State Department has suggested the US will support whatever government emerges if it continues the reformist path begun by President Duarte. But a rightist coalition will certainly make more difficult the Reagan administration efforts to win congressional and public support for its El Salvador policy, including plans to step up both military and economic aid.

For President Duarte, who stubbornly clung to election plans despite warnings dating to last November that he could lose, the combined 60 percent vote total of the opposition parties must be a bitter disappointment. Even more frustrating for him is the firm political leadership being displayed by Major Roberto d'Aubuisson. His quick maneuvering has apparently led to the arrangement between the five opposition groups.

President Duarte and his Christian Democrats were prepared to receive less than a majority--but they expected to do well enough to form a coalition government with the more moderate of the opposition parties.

Unless there is a major reversal in the trend, d'Aubuisson's political maneuvering virtually assures that El Salvador's next government will be one in which he plays the key role. He may not become president; in fact there is speculation that Accion Democratica leader Rene Fortin Magana could be tapped for that job. But d'Aubuisson will certainly be the key figure in the government.

As US officials here assess these events, they try to put the best face possible on the situation. There are numerous references to Sunday's vote as representing the will of the people in what was by all accounts a democratic, free, and honest election.

But there can be no masking US disappointment. Both the Carter and Reagan administrations went far to prop up the Duarte government. And the Reagan administration has moved rapidly in recent weeks to support a military victory over the leftist guerrillas who have been playing such havoc in this country for the past four years.

The guerrillas, with support in the countryside and in San Salvador, have grown stronger in recent months, but they did not take part in the election process, calling it a ''fraud'' and a ''sham.''

There was expectation that the guerrillas would try to disrupt the vote process. But with the exception of harassment of voters at some of the polling places, burning of buses that might have transported voters to polls, and destruction of some telephone facilities, election day went off without many hitches.

Most of the country has returned to normal after the busy day of voting Sunday. One would hardly know that San Salvador has been caught up in a virtual civil war between government and guerrillas; the streets of San Salvador are crowded with vendors and pedestrians. Except for the occasional Army patrols rambling through the streets and sporadic rebel firing in the distance, the guerrilla threat seems far removed.

However, the new government now being formed must deal with a guerrilla situation that includes insurgent occupation of a good portion of the northern provinces of Cabanas and Chalatenango and other isolated parts of the countryside.

Most of the military aid destined for the Duarte government is aimed at crushing the guerrilla forces. It is obvious that the voters--apparently about a million strong - were showing their own rejection of the guerrillas.