It was possible in Washington in the last week to talk with both sides in El Salvador about the burning question of whether there is any chance of getting a negotiation under way.

First, with Salvadoran president Alvaro Magana, a lawyer and economist with a streak of self-deprecating humor and a full sense of the difficulty of his situation. One can believe he knows his country's desperate need to wind down the war. No doubt things would be different if he were in charge. But El Salvador has only some of the forms of democracy, and there is a war on, and this gives the advantage in power to the armed forces, a generally conservative committee.

We journalists fenced with Magana over whether he could live with a demand that Congress wishes to attach to aid: that El Salvador enter a "dialogue without preconditions" with the left. Sure, he said. But then it turned out that there was a big precondition: his government will only discuss its own offer to the guerrillas to lay down arms and take part in the official elections. El Salvador would rather lose aid than accept Congress' bidding on dialogue, he ended up saying.

As one who believes that negotiation of some sort offers the best available answer --not an easy answer but one better than any visible alternative--I was sorry to hear Magana make so categorical a statement. It was only a slight consolation to consider that El Salvador's officials, who never seem fully prepared for the brusqueness and explicitness of American political/journalistic dialogue, tend to react with formulations that may be harder and more precise than they mean. Maybe.

More disturbing was that by his own account Magana was not familiar with a series of questions--reasonable questions, I had thought, bout the authority of his government's new "peace commission"-- that the Salvadoran left had asked in Mexico City 10 days earlier after the commission had appealed to the left for its own sort of dialogue. The Salvadoran press does not publish statements from what Magana calls "the subversion." The left calls the government of El Salvador, by the way, "the government of El Salvador."

Onward to Ruben Zamora, spokesman of the political wing of the guerrilla movement. A well-spoken lawyer known to many American journalists, he has some of the same personal qualities seen in Magana. One suspects that it would be easier to resolve the conflict in El Salvador if he were in charge on the left but that the weight lies with his comrades with guns. He is sensitive on the subject, maintaining that most guerrillas, being recent converts from politics, can readily switch back.

The left, Zamora said, has good practical reason to negotiate a settlement, not least its growing fear that its successes in battle may trigger an American military intervention. But that cannot mean just negotiating a role in the coming presidential elections. These, even with the democratic left's participation (out of the question, Zamora insists), will simply institutionalize an unrepresentative presidency. First and foremost, negotiation means making new institutional arrangements for the armed forces of the two sides. Only then can a cease-fire be accepted and elections arranged, Zamora says.

From all of which I conclude that Magana and Zamora have scarcely begun to cope publicly with each other's distrust and fear.

Magana boosts a plan, supported by the United States, that would require guerrillas or civilians who wanted to vote for the left to put their fate in the hands of the still unleashed death squads and the still unreformed security forces. This is an absurd proposition. Let Americans who ask the left to take the risk first see justice done to the killers of the American labor and church people. Nothing so far advanced publicly by the American or Salvadoran governments indicates that either is yet contemplating the difficult things that must be done if the left is to be drawn in.

Zamora slides past the fundamental, principled Salvadoran and American objection to granting power to a guerrilla force unlegitimized by popular choice. He says the left would win fair elections and respect the results if it did not. But the guerrillas, variously Marxist, totalitarian, anti-American, oriented to Nicaragua, Cuba and the Soviet Union, have not earned the credibility of those who do not share their faith. The requirement remains for gestures, commitments, procedures, arrangements that will close the gap.