San Jose, Costa Rica — The red brick office on San Jose's west side is undistinguished except for the dozen cars crammed onto its front lawn. Inside, however, the place jumps. Carpenters are throwing up room partitions. Secretaries bang on typewriters and phones ring incessantly. The hammering and banging almost screen the murmur of men's voices speaking in Spanish and Caribbean English behind closed hallway doors.
''The place of the Nicaraguans'' is how neighbors refer to the unmarked building.
''The place of the traitors'' is how Sandinistas would describe it.
Recently the office became headquarters of the Democratic Revolutionary Alliance (ARDE), a counterrevolutionary group whose stated mission is to ''rescue the Nicaraguan revolution.''
Its leaders are familiar faces both inside and outside of Nicaragua: former Sandinista war hero Eden (Commander Zero) Pastora Gomez, former National Reconstruction Junta member Alfonso Robelo Callejas, and Miskito Indian leader Brooklyn Rivera.
The men, now living in exile in Costa Rica, formed the alliance in September. They charge that the governing Sandinista National Liberation Front (FSLN) has strayed from the original goals of the revolution, which are political pluralism , a mixed economy, a free press, and free elections.
ARDE's leaders claim they will force the Sandinistas to fulfill the goals ''at gunpoint, if necessary.''
''We have the support of 2.5 million Nicaraguans (the entire population),'' boasts Mr. Pastora. ''The armed forces are behind us.''
The Sandinistas scoff at the claim.
''If he had all this support, why would we be such imbeciles as to give guns to our people so that they'd overthrow us?'' retorts Minister of Interior Tomas Borge Martinez.
Supporters claim the alliance represents a politically astute coalition with broad-based support in Nicaragua.
Other observers say that although ARDE has the potential for such support, it has not yet developed it.
The man at ARDE's helm is Pastora, a cult figure who led the historic 1978 raid on Nicaragua's National Palace. The mission won him the hearts of his countrymen and the nickname ''Commander Zero.''
Stocky and dark with flashing brown eyes, Pastora is still regarded as possessing the charisma he displayed in the Nicaraguan revolution against dictator Anastasio Somoza Debayle. When the Sandinistas ousted Somoza and formed their own government in 1979, Pastora was named deputy defense minister. Although he left the government, disillusioned, he reportedly continues to enjoy a certain hold among lower- and middle-class Nicaraguans and some segments of the armed forces.
The second key figure is Mr. Robelo, an original member of the National Reconstruction Junta who resigned in April 1980, charging that the FSLN had deviated from its original goals.
The businessman, who made his fortune in the cooking-oil industry, now heads the Nicaraguan Democratic Movement (MDN), a political party that operates out of Costa Rica. Articulate and personable, he is viewed as less impulsive and more guarded than Pastora. Robelo reportedly retains some backing among commercial and professional groups in Nicaragua.
ARDE's claim to favor among the 150,000-or-so indigenous residents on Nicaragua's Atlantic (Caribbean) coast comes with Mr. Rivera, the least-known member of the group. He was the elected leader of MISURASATA, an organization that claims to represent the three major indigenous groups on the coast - the Miskito, Sumo, and Rama.
Rivera's main support apparently comes from the southern Atlantic coast. His well-known brother-in-law, Steadman Fagoth Muller, reportedly still holds sway over much of the north. Young and aggressive, Rivera is known to be a fighter.
Although it appears to have significant public support, ARDE faces several problems in Nicaragua, knowledgeable observers there say.
For one thing, the only ARDE leader who continues to hold any real leverage in the country is Pastora, they say. And the longer he stays in exile, the more he loses it.
As for Robelo, Nicaraguan businessmen say he is ''a respected man'' but doesn't have a mass following.
''Robelo represents a political party (the MDN) which was very young and never very big in Nicaragua,'' notes a leader of an opposition party. ''The party now is completely disbanded and its leaders are in exile.''
Likewise Rivera's backing is difficult to gauge. He seems to provoke a love-hate relationship among Atlantic coast esidents. Some call him ''an opportunist'' or ''Fagoth's sidekick.'' Others claim he is ''No. 1'' or ''the real leader.'' ARDE strategy
ARDE's current strategy for overthrowing the Sandinistas is political, but the alliance does not rule out force if a political solution fails.
In fact, many regional observers think Pastora already is training his men. Costa Rican security forces supect that at least some of the eight abandoned camps they have discovered since January may be linked to ARDE.
ARDE says it is not allied with the militant right-wing Nicaraguan Democratic Force (FDN) - the counterrevolutionary group that recently slipped hundreds of rebel fighters from bases in Honduras into central Nicaragua.
''For now we're working on a political solution, and on raising the consciousness of the people,'' Pastora explained during an interview in his well-guarded home in suburban San Jose.
This has meant wooing influential disenchanted Nicaraguans as well as international leaders. ARDE is also courting European Social Democrats, who it hopes will pressure the Nicaraguan government to make reforms. Pastora has told journalists that he has the support of Spanish President Felipe Gonzalez and former West German Chancellor Willy Brandt.
ARDE also operates a prolific propaganda machine, cranking out an hour-long radio program that is broadcast nightly into Nicaragua.
The show appears to be fairly successful. An informal survey in Managua indicates that residents are aware of the broadcast, but few listen to it regularly. On the Atlantic coast, however, where many Nicaraguans have shortwave radios to pick up the transmissions, the number of listeners may be higher.
''One of the first things I hear when I go back home is 'Hey, did you hear what Eden said last week?' '' says a former Puerto Cabezas resident living in Managua.
As for more concrete activities in Nicaragua, Robelo says ARDE is creating ''an urban front that should develop in time to a penetration of rural areas.''
He adds, ''We're contacting people who might be organized if we have to resort to a means of force. . . . We're preparing the stick to hit with.'' Support within Nicaragua
But this will be no easy task, and ARDE refuses to list its contacts in Nicaragua, claiming this would be too dangerous.
Asking people on the street to talk about Eden Pastora is apparently a risky business. They avoid mentioning his name, and when they must, they say it in hushed tones.
Nicaraguans joke that the men who sell lottery tickets are afraid to yell out the number ''zero'' so they say the letter ''O.''
About the only tentative conclusion to be drawn is that Commander Zero draws some support from the Atlantic coast Indians, among certain small businessmen and market vendors, and among some disenchanted former Sandinista soldiers - especially those who fought alongside Pastora on the southern front during the revolution.
Even opposition parties are hesitant to throw their support behind ARDE.
''There doesn't exist a coordination between ARDE and the Democratic Coordinator (a committee of opposition political parties and labor unions),'' states Agustin Jarquin, general secretary of the Social Christian Party. ''They don't count on our support, but neither do they count on our rejection.''
Likewise the Superior Council of Private Enterprise (COSEP), a federation of major business and industry chambers, steers clear of links with ARDE.''
The people here try to avoid getting involved in politics,'' explains a COSEP official.
''If Pastora entered Nicaragua with a column of men, many people would follow ,'' adds another opposition party leader. ''There's a lot of discontent here, if he would just take advantage of it instead of sitting in Costa Rica.''
Some Atlantic coast residents agree.
''If tomorrow morning Eden Pastora would walk into town, things would start happening,'' predicts a former Bluefields resident living in Managua.
This Miskito Indian claims that the Atlantic coast is armed and angry. They're ready to fight, he says, but they need a strong leader. That's where Pastora fits in.
Another coastal resident points out that Pastora's links to the revolution could hurt his image.
''Pastora smells of Sandinista, and the Atlantic coast people don't want that ,'' claims a resident of Puerto Cabezas.
ARDE, in fact, struggles to maintain a ''revolutionary'' image. It recognizes that the vast majority of Nicaraguans supported the revolution. It even separated itself from one of its original members, Fernando ''El Negro'' Chamorro, because of his military activities and his ties to some Somocistas (supporters of Anastasio Somoza), observers say. ''We have to talk about the revolution, but not as contras, or the people won't listen,'' notes Pastora, who bristles when called a ''counterrevolutionary.''ARDE denies any association with former National Guardsmen (Somoza's army), the US Central Intelligence Agency, and the Nicaraguan Democratic Force.
But the FDN, comprised of ex-Somocistas and disenchanted Somocistas, has a political platform that is in some ways very similar to Pastora's. The group calls for what it considers free elections, a general amnesty, and freedom of expression. But unlike ARDE, it also favors reversing the agrarian reform program, returning land captured from Somoza, and freeing Somoza's National Guardsmen who were jailed.
The FDN's strategy is decidedly militaristic. It has urged ARDE to join it to create a united opposition, but the ARDE alliance so far has refused.
One reason for its refusal is that Pastora is pinning his hopes on gaining the support of Nicaragua's current armed forces, a sector Pastora says would never fight side by side with the FDN's ex-National Guardsmen. He estimates that some 240,000 men serve in some armed capacity in Nicaragua. (Other Western sources place the figure at closer to 160,000.)
''Our strategy is to divide this 240,000,'' Pastora declares. ''With their arms we will fight our revolution.''
Although Pastora won't disclose how many armed men he has in Nicaragua, ARDE political secretary Anibal Arana puts the number at about 5,000. Sandinista reaction to ARDE
Sandinista security officials jeer at Pastora's plans. Mr. Borge charges that the majority of his supporters ''are in the mind of Eden Pastora.''
Capt. Roberto Sanchez, official spokesman for the Sandinista Popular Army, dismisses Pastora's claims that the Army has a high number of deserters:
''The few people who desert don't bother us. It's not a theme that's brought up in military meetings,'' he says.
Many of the ''defectors'' that ARDE has attracted to date have been politicians. They include former Nicaraguan Ambassadors to Washington Arturo J. Cruz Porras and Francisco Fiallos Navarro, and former Nicaraguan Ambassador to Ecuador Alvaro Toboada.
The alliance, in fact, had big plans for Mr. Fiallos, who showed up at an ARDE press conference in San Jose within two weeks of his resignation last December.
''We are looking for a full-time adviser in Washington, since Arturo Cruz can only work part time,'' explains Robelo. ''We were hoping to make Fiallos that, or maybe our ambassador-at-large.''
But on learning of evidence linking Fiallos to the embezzlement of $600,000 from a Nicaraguan bank account, ARDE decided to ''hear from him again'' before making further plans, Robelo says.
Interior Minister Borge believes that ''for the moment'' the FDN presents more serious problems for Nicaragua than ARDE. But he hints that ARDE could become more dangerous in the future.
''To date, the CIA and the US government have fundamentally projected their support to the FDN,'' he observes. ''But I think they are holding ARDE as a last card for the future, in case the FDN doesn't manage to prosper.''
The stern interior minister also denies Pastora's claims that he holds influence with key leaders in the Socialist International.
''What these travels do is reaffirm Pastora's lack of sincerity,'' Borge claims. ''These leaders expect to find themselves with some top-level politician with great mental clarity, but what they find themselves with is some poor nobody.''
A Western observer adds: ''I think some of Pastora's travels may have influenced Socialist International and other leaders to become more critical of the revolution. But I don't know of any international organization that is laying its money on Pastora being the savior of the revolution.''