How much time do you give a revolution?

An almost self-conscious pluralism strikes the visitor immediately after clearing immigration in the spotless Managua airport. There, on one wall of the baggage recovery area, is an impressive streamer proclaiming the need for continuing revolution. On the next wall cornering with it is a large plastic four-part sign putting everyone on notice that American Express, Visa, Mastercard, and Diner's Club credit cards are honored in Nicaragua. Can this be the Marxist-Leninist state that Reagan aides have been anxious to destabilize?

There is more pluralism on the highway into Managua, lined with heroic-sized billboards of opposition parties, as well as of the ruling FSLN (Frente Sandinista de Liberacion Nacional). There is pluralism on our official program prepared by the Ministry of Foreign Affairs which calls for meetings with the COSEP (Superior Council of the Private Sector), as well as with the editors of the independent newspaper La Prensa. Among COSEP members are businessmen who led the shutdowns that destabilized Somoza at the crucial final stages of the revolution.

I would later meet with leaders of the opposition: Alfonso Robelo, former junta member and first president of COSEP; the Social Christian Adan Fletes Valle; the Social Democrat Wilfredo Montalvan; the Conservative Jose Castillo Osejo, who owns a radio station.

The fact that the meetings were possible at all appeared to substantiate government claims of ongoing pluralism. ''Show me,'' junta member Sergio Ramirez challenged us, ''another revolutionary country where no American company has been expropriated, where there is a free press and where there is private enterprise with incentives.'' (The government had just announced a new package of incentives for private exporters.)

In August 1981, La Prensa conducted a Gallup-style poll of Nicaraguan public opinion which showed a 60 percent disapproval of the Sandinista government. But Father Amando Lopez, the Spanish Rector of the Jesuit Universidad de Centroamerica in Managua told me: ''A revolution is miserable. The people expect immediate results. If 40 percent of them now favor the revolutionary government then it is an incredible success.

''The Sandinistas are not vanguardists,'' Father Lopez insisted, ''There are those among them who want to build Christian values.'' But the Sandinistas stand accused of acting like vanguardists, intolerant of opposition, and guilty of those things that a one-party government eventually gets tempted to inflict upon people--torture, arbitrary detention, massacres.

All human rights violations must be condemned. But no revolution must be viewed in isolation. Foreign policymakers can do so only at the peril of tragic miscalculation and disaster.

Some of the Nicaraguan opposition's pessimistic complaints might appear less desperate when viewed in the context of historical and current reality:

1. ''The government is going socialist, beginning to own so much industry.'' Forty percent of democratic Italy's industry is in government hands.

2. ''There are unnecessary restrictions on the press, like the ban on reports that cause 'panic buying' of basic commodities.'' In Malaysia, the nearest thing to a Southeast Asian democracy, there is a ban on ''racially charged'' reporting because of the precarious balance between Malays and Chinese in the population.

3. ''Why wait six years for elections in 1985?'' The first US elections were held seven years after the final victory at Yorktown in 1781, because the new republic was beset with economic restrictions imposed on it by Britain, Spain and even its former ally France, with military harassment by thousands of Tories who had fled to Ontario. The Sandinistas claim similar harassment by the US which has withdrawn aid, opposed World Bank loans to Nicaragua aid, and is now training Somocistas in various parts of the US for the obvious purpose of invading Nicaragua.

4. ''The Sandinistas have put businessmen in jail for criticizing the government, shut down La Prensa for a total period of 11 days.'' When John Adams became president, he got laws passed that did away with free speech and press freedom, silencing editors and critics with heavy fines or prison. Only when Jefferson became President were the jailed men released.

5. ''There have been tortures and massacres of political prisoners.'' Americans--blacks, Indians, striking laborers--were victims of torture and mass killings by US or state government forces for over 150 years from the founding of the republic. An early instance was the ''beneficial execution'' of scores of rebellious slaves in 1800 in Virginia.

How much time do you give a revolution? Even El Salvador's centrist Jose Napoleon Duarte believes that Nicaragua should not be destabilized because it ''has to have the opportunity to fulfill its own revolution.''

And Edan Pastora, the charismatic Sandinista who resigned from the cabinet last year and has just resurfaced in Costa Rica, wants not the destabilization but true independence from both Soviet and US domination.

Even the Nicaraguans who refuse to look to the Soviet Union and Cuba now seem to feel they must not look to the US but elsewhere. The US can still turn this policy tragedy around by reviewing the Nicaraguan revolution in the light of its own.