During a recent unannounced visit to one of El Salvador's key provincial Army garrisons, right-wing leader Roberto D'Aubuisson sat down in the commander's air-conditioned office, poured himself a glass of scotch whiskey and began his pitch.

"You know, one of these days all of us should get together in a meeting," former Army major D'Aubuisson told his host and former military academy classmate, an embarrassed colonel who allowed a visiting reporter to sit in on the meeting only on the condition that neither the colonel nor his garrison would be named.

"We can help each other that way. After all, we all share the same objective: the good of El Salvador," D'Aubuisson said.

Less than a month after President Jose Napoleon Duarte held preliminary peace talks with guerrilla leaders who have been fighting the government for five years, D'Aubuisson was out lobbying among his former Army officer colleagues for influence should the peace talks fail.

D'Aubuisson, a one-time military intelligence official, underground right-wing extremist, conservative presidential candidate and a man whom U.S. officials have singled out as one of the orchestrators of El Salvador's death squads, was out to try to win the hearts and minds of the Army that has officially endorsed, with unstated qualifications, Duarte's peace initiative.

The former major's pitch to the colonel and a handful of other officers who crowded into the office to swap jokes and glasses of whiskey with him was subtle and low key. As D'Aubuisson portrayed it, his call at the colonel's, like those at dozens of other garrisons he has visited in recent weeks, was merely a courtesy call made while in town visiting local officials of his National Republican Alliance, or Arena, as the political party he founded is known by its Spanish abbreviation.

Until he was asked by a visiting journalist, he made no mention of Duarte's meeting with guerrilla leaders Oct. 15 in the northern town of La Palma. Then he simply reiterated his party's official line that he does not so much oppose the peace talks as the manner in which Duarte held them. He said the talks will "ultimately fail," dangerously dashing the national hopes they have raised.

"I just dropped by," he said laughing, "to see my old classmate and have a social talk."

Classmates in the military academy are a close-knit group in El Salvador, with each graduating class forming an old boy network that they call a tanda, where loyalty counts more than political or personal differences.

It is a network that one U.S. military expert said D'Aubuisson systematically has been cultivating in the days since the meeting in La Palma.

"D'Aubuisson is again working his old constituency," the military expert said, "because he still has hopes that he can turn the Army against Duarte as he has tried to do several times in the past."

What makes D'Aubuisson's swing through the barracks important is that today D'Aubuisson's tanda dominates the Army. Members of D'Aubuisson's military academy graduating class hold 11 of the top 20 field commands in El Salvador's 38,000-man armed forces, including four of the country's six brigades, four of its seven regional garrisons, the artillery battalion and the cavalry battalion.

Only this week another classmate and former close ally, Col. Rene Emilio Ponce, was named chief of operations of the armed forces general staff. Other former D'Aubuisson supporters, of the graduating class that followed his, hold many other field commands.

Military analysts here warn that merely having classmates in so many key positions does not mean that D'Aubuisson has their automatic support. In fact many of his classmates, although they are prepared to defend him, are opposed to his extremism.

The importance of the tanda connections, however, lies in the entree they give D'Aubuisson into the garrisons where he also has the support of a number of junior officers. In the colonel's office the other day, many young officers pushed up to greet him, shake his hand, and call him "Colonel," the rank he would hold now had he not left the Army following a coup by reformist officers in 1979.

While insisting that he is not opposed to peace talks, D'Aubuisson subtly indicated his displeasure with Duarte's talks in La Palma, saying they gave international recognition to the rebel leaders of the Farabundo Marti National Liberation Front.

"I don't think anything can come of" the talks, D'Aubuisson said. "The armed subversives will keep fighting and will not give up their arms until they have gained power."

"What have we gained?" he asked rhetorically. "Nothing. The rebels have gained prestige, publicity and time."

The real danger, D'Aubuisson said in the barracks, is that when the talks fail, as he said they were bound to do, "morale will drop in the public at large, and also here in the armed forces."

Although he did not say so openly, that clearly is the moment he is waiting for to challenge Duarte's policy. That, it seems, is when he hopes more officers in the Army will again be willing to listen to him.

That such a time can come is something even senior military commanders admit in veiled terms when they discuss how the Army is now officially behind Duarte, a man it had long been suspicious of because of policies many officers used to call "communist."

Since taking over the presidency in June, Duarte has worked hard to court the military, especially the new generation of officers who have moved into key commands during the past year. Men like Gen. Carlos Eugenio Vides Casanova, the defense minister; his deputy, Col. Carlos Lopez Nuila; chief of staff Col. Adolfo Blandon, and key field commanders such as the late Lt. Col. Domingo Monterrosa and Col. Sigifredo Ochoa, have been consulted by the president, taken on his trips abroad, invited to state banquets and otherwise courted.

It is a policy that has paid off for Duarte so far, especially because he has also succeeded in getting more military aid from the United States than ever before.

"On the one hand, he has flattered them," said a foreign military analyst. "On the other hand, he has delivered for them."

Blandon said as much in an interview in which he stressed that the Army hierarchy supported the civilian president despite past reservations about him.

"The reason," he said, "is that through our contacts with him in the days since his election he has shown -- for the moment -- that he does not have communist leanings."

Asked about what he meant when he said, "for the moment," Blandon laughed and said he was a man who dealt with realities and could not foresee how things would be or appear in the future.

"Let us say we are satisfied now," he said.