Duarte's task

THIS is a crucial week for Jose Napoleon Duarte: The newly elected Salvadorean President is trying to sell himself to the United States Congress - and to the American people. His immediate objective is to pry from the US House already approved by the Senate.

Beyond that, he seeks to take a first step toward convincing Congress and the US public that he is committed to and capable of controlling his country's wealthy elite and its military and reforming the latter, ending activity by right-wing death squads, rebuilding the Salvadorean economy, reactivating land reform, and bringing peace to his embattled nation. He says he can do all this, yet clearly it is a tall order.

He deserves US support: He will need money for economic purposes and to hold off the guerrillas. And he will need to be given time to make the necessary changes. It is important that he succeed, as the alternatives are unpleasant to contemplate.

Once Mr. Duarte is officially inaugurated President on June 1, he then must act on his reform promises. He will need to demonstrate to skeptical observers in the US and elsewhere that he has the power base necessary to control the Army and the wealthy oligarchy: Together they have dominated their nation and its government for 50 years. This can be done only by standing up to both.

Controlling the Army will enable him to reduce death-squad activity dramatically - essential if the government is to win the support of neutral peasants in the country.

A new report by Amnesty International on right-wing violence indicates once again its scope, and thus the challenge of ending it. The report, however, is based on a visit to that nation more than 10 months ago. The systemic problems the report noted doubtless remain, and are much in need of improvement.

Yet by most accounts the violence dropped dramatically early this calendar year; thus the situation may now be considerably improved, compared with what it has been.

While Duarte's immediate concern in the US is with relations with Congress and the public, there are points to discuss with the Reagan administration as well. One is whether the growing US military activity elsewhere in Central America, primarily in Honduras, is on balance helpful to the Salvadorean effort.

Or, on the contrary, whether it is helping to create a climate that is overly militaristic at the very time that El Salvador needs to find a way to stop its internal war through diplomatic means. In this connection it would be helpful to Duarte if the Contadora peace process, now apparently stalled, instead were active and making progress.