In 1979, we tried to install an era of democracy. Instead, what we got was another dictatorship. --Jose Cardenal, an anti-Sandinista Nicaraguan

JOSE CARDENAL IS an intense man with dark brown eyes who seems to have trouble sitting still. Several times during our conversation in a cramped Cambridge motel room, the middle-aged Nicaraguan began to answer a question only to get up, rummage through a briefcase on the nearby bed, pick out a thick file, and sit down again. The files remained unopened on his lap; I sensed that Cardenal was using them as symbolic justification for the points he was trying to make. But even without concrete proof, the Nicaraguan's arguments against the ruling Sandinista junta were often convincing and disconcerting for a liberal listener.

Like the overwhelming majority of Nicaraguans, Cardenal took part in the 1979 revolution that ousted long-time dictator Anastasio Somoza and installed the Sandinistas. But Cardenal--a politically middle-of-the-road civil engineer--claims the Sandinistas now in power betrayed the spirit of the revolution. "The Nicaraguan people were united against Somoza," he says, "there was no ideology involved. But in the confusion after the fact, the Marxists took over. They are the ones running things now."

Cardenal left Nicaragua in the spring of 1980 to lecture in this country against the Sandinistas and organize a coherent opposition. He speaks with dismay about the country he left behind, "controlled in effect by Cuban advisors, lacking the basic freedom of the press, and without the prospect of open elections for the future."

Were Cardenal a former Somoza follower, his arguments could easily be dismissed. But the counterre volutionary is part of a growing number of anti-Somoza Nicaraguans fighting the Sandinistas. And Cardenal argues that these "freedom fighters" deserve the backing, not the hostility or indifference, of the United States.

The Carter Administration is partly to blame for the current state of affairs, Cardenal believes. While Carter was instrumental in pressuring Somoza to step down, he did little to insure that moderates succeeded the dictator. A power-vacuum evolved, Cardenal claims, not unlike the one in 1917 Russia, and "the wrong people took the prize." What Cardenal cannot understand is Congress' reluctance to put pressure on the Sandinistas. "The United States did the right and noble thing getting rid of Somoza. Why all this hesitation about the Sandinistas? It is the same problem."

BUT MANY liberals in this country argue that the Sandinistas haven't been given a chance. Although Carter doled out more than $200 million in funds to Nicaragua in 1980, the Reagan Administration quickly cut all American assistance and hinted that an invasion--either covert or overt--might be imminent. The Sandinistas, the liberals believe, have simply been forced to react to this pressure by seeking help from Moscow and Havana and engaging in a military build-up.

This line of reasoniong, says Cardenal, is a naive way of looking at reality. The ruling junta was Marxist from the start, he claims, and is using perceived U.S. bellicosity as an excuse for authoritarian rule. "They had no intention of doing things any differently," Cardenal argues. The ambiguity of American policy though, has given Sandinista actions legitimacy in the eyes of many third parties.

While reports that Washington is financing counterrevolutionaries to overthrow the Sandinistas abound, Cardenal says he has seen no evidence of this assistance, though he would be happy to have it. But he believes overt aid will be difficult to obtain in the near future because of the negative way in which the counterrevolutionaries are portrayed by the U.S. media. "We are always called invaders," Cardenal complains. "General de Gaulle wasn't an invader, he was a liberator, So are we."

Some of the "facts" that Cardenal uses--for example, "90-percent of the Nicaraguan people are against the Sandinistas"--are impossible to verify. Yet he carries a certain authority, a certain legitimacy, simply by virtue of having lived in Nicaragua. It's hard to debate Cardenal when you've never set foot in Central America.

BUT WHILE Cardenal's arguments raise serious questions about the viability of the Sandinista regime, counterrevolution is not necessary--yet. Overthrowing the Sandinistas must be seen as a policy of last resort, to be contemplated only after all other means of change have been attempted. For despite the authoritarian nature of the regime, it is a ten-fold improvement over Somoza and Co.: great strides have been made in education and literacy and torture is no longer a fact of life.

More important, ousting the Sandinistas would in no way ensure a democratic government for Nicaragua. The present opposition is so diverse that there is no telling which of the many factions would take power. Certainly the presence of many former National Guard members does not inspire confidence in the possibility of a liberal--and democratic--replacement for the Sandinistas.

The wisest course would be for Washington to try a little experiment. The Administration should withdraw any support it is supplying to the counterrevolutionary groups and pressure them to cease their activities. The government should then restore aid to the Sandinistas and initiate negotiations aimed at easing tensions between the U.S. and Nicaragua. For their part, the Sandinistas would have to liberalize their rule and schedule elections for the near future.

Of course, such an experiment might easily fail. If Cardenal is right, it will fail. But the gamble seems worth it. After all, if another civil war isn't necessary, we should try everything possible to avoid one. And the Sandinistas, despite increasing signs to the contrary, might still be worth salvaging.