Tread the narrow, twisting corridor of ifs and maybes that leads toward a negotiation in El Salvador, if and maybe.

True, the fighting goes on. Among the would-be peacemakers there is evident neither the authority on their own side nor the trust on the other side to make a negotiation go. The smart money says forget it.

But two considerations work against this forbidding prospect.

The less important is that everyone now pays court to the idea of a negotiated settlement. The Salvadoran government has created a "peace commission," whose equivalent already exists on the left. The patrons of both sides, including the United States, Cuba and assorted others, say they favor talks. The would-be mediators of the Contadora group have made contact.

So there is 1) if not an impulse to peace, a pretense to peace among the parties, 2) a body of supportive international concern and pressure and 3) the beginnings of some mechanisms.

All this and 10 cents buys a cup of coffee, or used to. The more important consideration snapped into focus for me only this week as a result of encounters with Deane Hinton, until recently the American ambassador to El Salvador, and Jeane Kirkpatrick, President Reagan's representative to the United Nations.

What I took from them was the feeling that the Salvadoran sides are not nearly so far apart as is commonly supposed, but that at the political level the administration is not fully aware of how it might bridge the gap.

Hinton is a crusty old pro with a background in economic negotiations. Though he is wary of the pitfalls, his premise--not his prediction--is that a negotiation can be made to happen in El Salvador if the United States hangs in with aid and plays its diplomatic cards right. He sat me up straight with his observation that, even as matters stand now, the Salvadoran government could "take on"-- somehow deal with --no fewer than four of the six points on the guerrillas' agenda.

What?

If you put "elections," shorthand for the government agenda, against "power sharing," Washington's shorthand for the guerrilla agenda, it's a mismatch. Between disposing of power by an election and carving up power before an election, there is no common ground.

But both agendas list, for instance, an item on security. The government invites the guerrillas to talk about the security arrangements requisite to their participation in elections, while the guerrillas ask the government to make a new disposition of their respective armed forces. There is plenty to disagree about here, but the two positions are not mutually exclusive.

On this agenda point and some others, Hinton believes, the need is to get the two sides talking. I found what he said an eminently practical basis on which to try to move the Salvadorans past shadowboxing.

So much for breakfast. At lunch it was Kirkpatrick, who, unlike Hinton, remains engaged in Salvadoran policy and enjoys the president's confidence.

Did she think it possible or desirable to encourage the Salvadoran sides to go to the table without prior agreement on the agenda? She could, perhaps, see the two arriving at the table, she said, but she doubted the Salvadoran government would conduct substantial conversations on an agenda not basically oriented toward the organization of elections.

Would not a good purpose be served by getting the two to talk? The unambiguous American position, Kirkpatrick said, is that the distribution of power can be solved by free elections with the broadest participation and security for all.

Are not discussions possible on the basis that the Salvadoran government acknowledges that the security of the left must be ensured for elections, while the guerrillas want a reorganization of the armed forces? No, she said, it didn't seem probable, it was not going to happen.

Why not encourage the two sides to sit down without an agenda, with the formation of an agenda the first item of business? The Salvadoran peace commission will sit down to discuss the left's participation and security in elections, she said, not the restructuring of the government before elections.

Maybe I got it wrong. Maybe she was just being properly discreet and deferential to the Salvadoran government. Maybe there is more flex in the administration position than meets the eye. But I sure had the impression that where the Hinton line might open things up, the Kirkpatrick line might close things down. It didn't sound good.