It is understandable that the United States should want to give the El Salvador government a fair chance to survive and prove its worth. But the American public cannot but have misgivings about pouring in more and more US military and economic assistance without clear-cut evidence that the government is stopping the killing of unarmed civilians and gaining popular support. President Reagan's plans to provide $55 million more in emergency military aid now and to boost economic aid in the next fiscal year come in the context of growing concern about insufficient progress either in stopping the government violence or in pursuing a negotiated settlement of the civil war.
Unfortunately, judgments are difficult because of lack of conclusive information. Both sides -- the government forces and the guerrillas -- tend to exaggerate their victories and their opponents' resort to naked violence. The Reagan administration apparently feels confident enough to state that the junta has made a ''concerted and significant effort'' to protect human rights. Yet the American Civil Liberties Union only last week charged in a lengthy report that the Salvadoran armed forces are responsible for a ''widespread and systematic pattern of gross violations of human rights.''
Reports that government forces killed several hundred civilians in the village of Mozote in December may indeed be exaggerated, as the US State Department believes, but there have been enough eye-witness accounts of junta troops indiscriminately attacking civilians during military operations to conclude that the problem remains widespread. On the face of it, it is encouraging that the Duarte government will soon indict six national guardsmen on charges of murdering four American churchwomen in 1980. But who, it may be asked, gave the guardsmen their orders and why are they not in the dock?
The rebel forces, too, engage in violence and are doing everything possible to disrupt upcoming elections for a national assembly. But the fact remains that, after such a long history of official repression in El Salvador, the onus is on the Duarte government to prove that it can control the military and is effectively curbing the terrorism. How can it hope to persuade the Salvadoran people that it offers them something different from their oppressive and brutal past? It is not surprising that many Salvadorans are ready to support the leftist guerrillas out of a sense that things could not be much worse in any event.
This is not to fail to recognize that President Duarte is a leader of good will and serious intentions. His government has managed to carry out a major land reform, though it is turning out to be less extensive than originally hoped. The fact that the nation's private sector is so critical of government policies suggests the reform efforts are meaningful. It is also only fair to note that Mr. Duarte's efforts to reduce the killing of civilians has had a measure of success. The situation in El Salvador is far less severe than in neighboring Guatemala. Yet it does not appear that Mr. Duarte is in full control of the military and able to work his will on it.
How much aid the US government should or should not provide in such circumstances is hard to say. Certainly it should not lose its leverage for constructive political change by cutting off aid altogether. But rushing in with increasingly larger and larger amounts has its risks if not accompanied by continuing pressure on the Salvadoran military and -- most important -- by parallel efforts to achieve a peaceful resolution of the conflict. The future of El Salvador should not be decided on the battlefield but in political negotiation -- with the US enlisting Mexico, Venezuela, and others in the region to help deal with the dangerous situation. There is little evidence yet that the administration is open to such a course.