Buenos Aires — The United States has found just enough flexibility in Argentina to continue its efforts to end the Falkland Islands conflict.
But patriotic fervor and the shaky internal position of this country's military rulers appear to have placed severe limits on how far they can move toward a compromise.
After more than 11 hours of talks with Argentine officials, US Secretary of State Alexander M. Haig Jr. flew back to London April 11 with new ideas aimed at resolving the Falkland Islands crisis. Haig is seeking the withdrawal of Argentine troops from the island in return for concessions from Britain, which has dispatched a fleet to retake the islands.
But, according to present plans, Mr. Haig would not reach London until after the British deadline for enforcement of a maritime exclusion zone to be applied to all Argentine ships within a 200-mile radius of the Falklands. With the British fleet of some 30 vessels on its way toward the Falklands and with some British submarines already reported in the area, London has said that as of 12: 01 a.m., April 12, Falklands time (11 p.m. eastern standard time, April 11), Argentine ships within that zone are liable to attack.
The United States would like would like both sides to draw back from military action and agree to a cooling-off period in hopes reason--and diplomatic solutions--will eventually prevail.
It is believed that one of the ideas Mr. Haig carried to London was for an international peacekeeping force to replace the Argentine troops now occupying the islands. But Argentine officials have made clear that they will neither renounce their claim to sovereignty over the islands nor permit the return of British troops to the islands.
A nation of 28 million people long known more for its divisions than for its unity, Argentina has been united as never before over the issue of the Falkland Islands.
Argentine journalists say that any government that made major concessions on the issue would be quickly forced from power. The current military government is in a particularly delicate position because of its unpopularity and because of allegations of economic mismanagement. Argentina has a foreign debt of $35 billion and as many as half of its industrial machines are lying idle.
Labor unions held a large demonstration against the government only a few days before it invaded the Falkland Islands. Riot police arrested more than 1, 000 of the demonstrators. The invasion at least temporarily relieved the pressure from that quarter.
On April 10, even as Mr. Haig met nearby with Argentine officials, a crowd estimated at more than 60,000 gathered at the same square where the labor unions had demonstrated earlier. This time the crowd was there to support the takeover of the Falklands. In addressing the crowd, the Argentine President, Gen. Leopoldo Galtieri, was cheered when he described the firmness of the government's position in the conflict over the Falklands, known here as the Malvinas Islands.
Galtieri, a tall, blue-eyed, white-haired military man who looked ill at ease in his speechmaking role, got the Argentine equivalent of boos--whistling--when he referred to himself as the representative of all the Argentine people.
''Galtieri got the message,'' said an Argentine political analyst. ''The people let him know, 'You cannot step back on the issue of the Malvinas. No matter what comes, we support you in the fight for the islands. But we do not support you as the representative of the people.' ''
''These people think that this is a football game,'' said the proprietor of a book store in the heart of one of the European-style capital's most fashionable districts. ''They don't know what a war is all about. They don't realize that this is serious business.''
The economic cost of the Falkland Islands invasion is becoming clear to some Argentines. Economic sanctions imposed by the European Community against Argentina have the potential for causing severe damage to the country's economy. The cost of transporting Argentine troops and supplies to the Falkland Islands, which lie about 400 miles off the Argentine coast is estimated at more than $500 million.
''In the end, only the Russians will profit from a war,'' said a Buenos Aires taxicab driver.
The Soviet Union's news media have begun criticizing Britain for its position in the crisis. Moscow is believed to be attempting to exploit the situation in order to enhance its standing in Argentina. The Soviets are currently the leading customers for Argentina's exports of grains.
According to foreign diplomats, there is an element of irrationality in the Argentine position on the Malvinas that makes it difficult to predict Argentine moves, but equally difficult to imagine that the military junta will agree to much of a compromise.
Diplomats say the main reason for the Argentine invasion of the Falklands was not the evidence that there are oil deposits near the islands. Oil is given as a leading cause in some foreign capitals. But the diplomats contend that the main impulse was patriotism and a desire on a part of the junta to use external conflict to divert attention from internal strife.