El Salvador's leading conservatives, long considered a major obstacle to any accommodation with rebels opposing the government, have reacted to President Jose Napoleon Duarte's unprecedented meeting with rebel leaders earlier this week with uncharacteristic moderation.

To the surprise of even Duarte, the conservatives have not so much criticized the meeting as the fact that they were not represented in the talks at the northern mountain village of La Palma last week.

"Our official position is that we must find a mechanism for achieving peace," former major Roberto D'Aubuisson, the leader of the country's powerful conservative Republican National Alliance (Arena), told reporters after Monday's meeting. "But these mechanisms must not just involve talking to the rebels but to the whole population."

D'Aubuisson, who narrowly missed defeating Duarte for the presidency ealier this year, said he did not oppose national dialogue but did object to the fact that the La Palma talks were behind closed doors and involved only what he considered a "narrow" segment of El Salvador's political spectrum.

"I don't consider what went on a real dialogue," D'Aubuisson said. "It was a monologue between old friends because Duarte and Guillermo Ungo have long shared the same political space and both share the same socialist ideas."

Ungo, a social democrat who heads the rebel guerrilla alliance's political wing, the Revolutionary Democratic Front, led the four-man delegation at the La Palma talks. He was Duarte's vice presidential running mate during presidential elections in 1972 that were overturned by the Army in favor of its candidates. Duarte, a Christian Democrat, is often described as a "leftist" by D'Aubuisson and his supporters.

D'Aubuisson's line was backed by his deputy party leader, Hugo Barrera, considered a more moderate rival in the Arena party.

"I think the La Palma meeting was not representative; it was a meeting of the Salvadoran left only," Barrera said in his seventh-floor office in the Legislative Assembly building. "In the last elections there was at least a 50-50 split between the votes of the right and the left here. For the meeting to have had real significance the right as well as the left should have been included." The leftist parties belonging to the guerrilla alliance's political wing did not participate in the election.

Barrera said that his party's reservations about the meeting hinged on the fact that they do not know exactly what went on inside the church at La Palma and what compromises Duarte might have made with the rebels that he has not revealed yet.

Arena leaders also made it clear that although they are not opposed to dialogue in principle, they insist that any settlement reached through negotiations adhere strictly to the constitution that they helped write last year.

"The government has said its position is that the talks must be within the framework of the constitution," Barrera said. "That limits and defines everything."

According to Arena's interpretation, and that of the armed forces, what that means is that the government cannot negotiate a role in government for the rebels as they have demanded. Instead, the only formula for a settlement allowed within the constitution, according to conservative leaders, is for the rebels to cease their armed insurgency and to enter the political and electoral process established under the constitution.

Barrera said the mere fact that the guerrillas had accepted to sit down with Duarte, at the president's invitation, implied their acceptance of the constitutional conditions that he had imposed as the basis for any discussions, even if the rebels have not agreed to them publicly.

"The question of the future is not what they the rebels say or not or what Duarte says or not," said retired Col. Jorge Alberto Jarquin, an Arena party assembly deputy representing Cuscatlan province. "But whether the constitution accepts them."

Jarquin said, however, that his party had yet to take an official position on the talks because it still did not have enough information about what precisely had gone on between Duarte and Ungo.