The El Salvador peace talks have produced a political impasse - and a concrete step forward with the signing of a Christmas truce between guerrillas and Salvadorean military representatives.
These somewhat contradictory results, say United States and Latin American analysts, make clear both the limitations and the usefulness of the negotiations as a way out of the longstanding conflict.
These analysts, who are political moderates here and in Washington, say that a settlement of the larger issues at stake between the Salvadorean guerrillas and the government of President Jose Napoleon Duarte is not possible at this time.
But they also feel that the results of the latest round of talks last Friday showed the negotiations' potential for:
1. ''Humanizing'' the conflict.
2. Acting as a useful channel of communications until the time when changed military and political conditions in El Salvador could permit serious movement toward a settlement to begin.
President Duarte cannot even begin to discuss any serious concessions to the guerrillas until he gains greater control of the Army and curbs the influence of the country's extreme right wing led by Roberto d'Aubuisson, these sources say.
Nor, they believe, are either the government or the guerrillas willing to go very far in making concessions until the military balance swings decisively in favor of either one side or the other.
According to one observer, Lionel Gomez, former leader of the Salvadorean land reform program who fled the country after receiving death threats, what happened on Friday was that, ''The guerrillas asked for things which they knew Duarte would not give; and Duarte, in turn, hid himself behind the Constitution in order not to have to admit what is really happening in El Salvador - that is, that he can do nothing serious because the Army and the extreme right won't permit him to.''
On Friday, the guerrillas made a detailed proposal for a long-term settlement in El Salvador. They asked, among other things, for:
* A division of the country into zones of control. In effect, this would mean a formal recognition of the fact that the guerrillas control certain parts of the country.
* Political power-sharing between the guerrillas and the government.
* Integration of guerrilla forces into the Salvadorean Army before national elections are held.
Duarte, although not present at Friday's talks himself, publicly rejected the proposals.
Mr. Gomez says that although the guerrilla demands were not unreasonable in themselves, they were totally unreasonable at this early, tentative stage of the negotiations - especially in view of Duarte's delicate political situation. Especially unacceptable to the Salvadorean military, he adds, were the demands for integration of the two military forces and political power-sharing.
Gomez further criticized Salvadorean insurgent leaders for not doing anything to make it easier for Duarte to make concessions or to build up his base in the Army and among the more moderate members of the upper and middle classes. Gomez specifically criticized the guerrillas for failing to make a statement indicating there are extremists in their own ranks who have been guilty of assassinations and other human rights violations, and who should be separated from the rebel movement.
According to Gomez, even moderate Army officers and members of the Salvadorean oligarchy, people who potentially favor negotiations and who Duarte needs in his struggle with d'Aubuisson, are terrified of the ''crazies'' in the guerrilla ranks. These moderates, he says want to see some distancing of the rebel military and political leaders from the extremists before they rally behind either Duarte or peace efforts.
Analysts in the US Congress and moderate Central American observers, as well as Gomez, stress the importance of Duarte building up his base in the military and getting rid of some extreme right-wing officers as a prerequisite for any further progress in the negotiations.
One moderately liberal US Senate source says that he does not expect much change in the Salvadorean military situation until January or February, but that a strengthening of Duarte's position then will be crucial. If the talks are to continue successfully, he says, some further concrete agreement (such as the prisoner exchange agreed upon in the October round of talks or the truce agreed upon last Friday) must be reached.
Much discussion centers around why the rebels raised controversial points last Friday. One prominent Central American member of a think tank in Mexico City, a man who is very knowledgeable about guerrilla affairs, believes that the Salvadorean rebel leaders in Mexico decided to put the bulk of their proposals on the table now because, given what they saw as Duarte's shaky position within the Army, they were uncertain if there would be a third round of talks. They felt it was important, he says, to put theirproposals on the record.
One basic question is: whom do the guerrillas really want to strengthen?
One classic Marxist argument is that a reformist government that wants only limited change is more dangerous to a revolution than a reactionary government that refuses all change and radicalizes the population.
The Central American think tank member says the rebels have to decide whether they will accept that argument (and indirectly strengthen d'Aubuisson by weakening the talks) or strengthen Duarte by being cooperative in the talks. (D'Aubussion was expected to speak in Washington late Tuesday at the invitation of some conservative US groups.)