"Over movement is very different," explained a prominent leader of Nicaragua's Sandinista Guerillas, just back from a Latin American tour. "While other revolutioniaries enter banks to assault them, we were just received in Ecuador by the president of the central bank."

Although the Sandinistas admit they have robbed numerous banks themselves in leaner years, it is becoming a fairly common scene for a delegation of Sandinista guerrillas to arrive at a foreign airport and be whisked away in official cars to see high government officials, sometimes a Cabinet minister or the president himself. In the last few months of newly gained respectability, Sandinista leaders have paid such "official" visits in nine Latin American nations.

The irony of the situtation has not escaped governments and Amderican diplomats in this region. While the United States is seeking a solution to Nicaragua's crisis that will exclude the Sandinistas, international support for the guerrillas in Western Europe as well as Latin America continues to grow.

Most government officials tend to be discreet about their sympathy or direct support for the guerillas, but other politicians are more outspoken.

"The Sandinistas have tremendous goodwill and public opinion on their side in Latin America," said former Costa Rican President Jose Figueres, whose son recently joined the guerrillas against his father's will. "I'm afraid the Americans won't recognize this."

The three Sandinista leaders who jsut returned from the Latin American and European capitals declined to disclose details of their talks with foreign governments but said the topics included requests for political and financial help and "seeing who would recognize a provisional government" if the Sandinistas took over an area of Nicaragua.

Confident of support abroad and popularity at home, the Sandinistas predictably have now come out strongly against the Nicaraguan plebiscite sponsored by the U.S. organized international mediation team and the Sandinista statements, it is widely believed, may well jeopardize the success of that effort.

Tentatively scheduled for Feb. 18, the plebiscite is advocated by American diplomats as the best solution to prevent a guerillas victory while ending the country's bloody civil strife. It would allow the population to choose between the long-time Somoza administration and a new coalition government.

While in principle both Somoza and the opposition coalition have agreed on a plebiscite, there are still differences about conditions attached to it.

The most serious obstacle, which may well render the American solution unworkable, is disagreement about a package of measures designed to provide a transition to democracy after the plebiscite.

Sources close to the mediation team say the package seeks to avoid "a power vacuum" after Somoza leaves. It would leave the rubber stamp pro-Somoza Congress intact, divide Cabinet posts between Somoza's supporters and opponents, and require selection of an opposition president who must be acceptable to Somoza's Liberal Party.

"It's an insult, it's absured," scoffed one prominent opposition leader in an interview. "Rather than promoting change, the U.S. only seems interested in the docility of the new team, however unpopular it may be."

The post-plebiscite scenario together with the Sandinistas' rejection of the plebiscite have produced the most serious crisis within the opposition coalition so far. Although three of the 15 political, labor and civic groups had already withdrawn from the mediation effort, the last 48 hours have produced heated internal debates about when other groups would withdrawn.

"Several groups believe the time has come to boycott the plebiscite," said Alfonso Robelo, a coalition leader considered to have close ties to the United States. "If the guerrillas, the students and the grass roots groups all oppose it, we may lose it, so we may be better off pulling out now."

Robelo said he was deeply worried about the way the coalition "is losing its prestige and credibility by yielding to too many American demands and concessions to Somoza."

Robelo, who has been repeatedly outvoted within the 12-member coalition, said one such concession included sitting down for direct talks with Somoza representatives, which took place for the first time earlier this month.

"One of our greatest problem is that the emotional level of hatred against Somoza is so deep here that anything that means dealing directly with Somoza automatically discredits one. There have been too many sell-outs in the past. Public opinion is now simply: Somoza must go. We won't make any deals," robelo said.

Although the United States put together a mediation team to end Nicaragua's growing instability and bloodshed at the request of many Nicaraguans, the current U.S. strategy in Nicaragua is increasingly criticized as not likely to produce a viable solution.

This criticism surfaced in numerous conversations with regional diplomats and government officials as well as American diplomats who watch Nicaraguan developments closely. These critics almost unanimously pointed out that on the one hand the United States has given undue emphasis to the unrepresentative conservative figures who - although in the opposition front - have little popular support.

On the other hand the critics said it was a policy error for the United States to alienate the Sandinistas and to refuse contacts with even the most moderate faction among them.

Persons who acted as go-betweens said that before and after the September civil war U.S. officials spurned overtures by members of the "Tercerista" faction, which is largely non-marxist and controls the Sandinista army.

Yet at the same time the Tercerista faction has attracted wide attention and curiosity both in Western Europe and in Latin America, the result no doubt of its political diversity and large component of middle class members.

In recent months, Tercerista leaders have met with high officials in Canada, Mexico, Panama, Venezuela, Costa Rica, Peru, Ecuador, Jamaica, Colombia and the Dominican Republic. In the last two countries they were applauded in plenary sessions of Congress.

At the Socialist International meeting in Vancouver last month, Western Europe's social democratic parties gave broad support to the Sandinista leaders in public while privately pledging $50,000 in contributions per month for the movement.