True, Sofia Montenegro is an extreme case. Twenty-eight, partly American-educated, she is the daughter of an officer who fought with the Marines and the sister of a Somoza major, a "traitor" who died fighting the revolution she now serves as an editor of the Sandinista newspaper and a member of the militia. To her, the United States is a country that has invaded, in turn, Nicaragua (four times), Europe, Korea and Vietnam and that may now unleash B52s and a fifth invasion on Nicaragua, killing perhaps 2 million people. Her paper's new comic strip depicting the Vietnam War is meant, she says, to condition Nicaraguans to the trials to come.

Other Sandinistas are more restrained. Foreign Minister Manuel D'Escoto, for one, believes an intervention possible but not probable: consistent with the GOP 1980 platform and Ronald Reagan's ideology, but not convenient at this time. The president of the central bank says simply that he resents past American support of the Somozas but wants the United States now "to consider us a small country that wants to be itself."

The prevailing spirit is, nonetheless, as the interior minister recently told the nation, "For all practical purposes, the U.S. has declared war against us." In this spirit, the junta is expanding its army to 50,000 and the militia to 250,000--against what Sandinistas view as an ongoing American destabilization campaign and against possible military operations ranging from a "Bay of Pigs" assault by former Somoza soldiers (and Argentines) all the way up. The same spirit animates the Soviet-like slogans, covering seemingly every vertical surface, exhorting people to labor, sacrifice and if necessary die--and meanwhile to turn off the electric lights--for the revolution. In this spirit, the junta has been crowding the limits of its professions of respect for pluralism at home.

To be sure, it was from the start a revolution of the left, with a strong Marxist streak and crucial Cuban support. But it was also a revolution with moral authority and popular support. Now many who rendered that support bemoan the results. They fear the junta is turning on them, notwithstanding the internal turmoil and damage to international standing that would surely follow from a further giant plunge down the Cuban path.

On the surface, pluralism lives. But the private sector trembles at its vulnerability to official sufferance. The junta is playing off a corps of revolutionary priests against the hierarchy. In labor, as with youth and other social groups, official organizations are being built up as vehicles of state control. A new draft press law would give the government a legal basis to shut down the lone voice of the opposition, La Prensa, which has already been closed five times by decree--once for suggesting that a honeymooning Prince Charles be sent a hammock and a book by Carlos Fonseca, one of the revolution's saints.

The army, police, TV and so on are already organs of the Sandinistas, not the state. Good people receive threats of jail, exile, even death. The mob has already been twice at La Prensa's door.

"A revolution is something that divides," the rector of the Jesuit university observed to me, acceptingly. "One must choose," said Sofia Montenegro.

How is one to judge all this? The revolution can boast high achievements: ending a detested dictatorship, initiating popular reforms--a literacy campaign, a sensible conservative land reform, improving the diet, clinics, etc. It behooves Americans, whose past record in Nicaragua is shameful, to respect the legitimate impulse for change. Our lectures on Sandinista lapses are inevitably contrasted to our solicitude for Anastasio Somoza's thuggery.

But the requisite deference, stirred for some of us by a touch of liberal guilt, does not require us to grant the revolution carte blanche. As a journalist, I am not going to make the junta's excuses for leaning on La Prensa. Least of all are we required to overlook or "understand" Nicaragua's support of revolutions beyond its borders. Though many Sandinistas do not accept that this is our prime concern--they fear Reagan is bent on destroying their revolution regardless--I do.

I am not up to saying whether American hostility is, as Sandinistas suggest, a cause or merely a pretext of Nicaragua's internal move leftward. But I will report that five days in Managua have left me convinced that the Sandinistas have a profound commitment to spreading revolution--to be true to themselves, to sustain their own power, to pay a debt to Fidel Castro, or whatever. This is not a crowd to lie low for a few years and consolidate--the policy common sense dictated when they won power in 1979.

The "evidence" that, incredibly, our State Department has been unable to muster lies, unclassified, all over Central America: in the availability of arms and ammunition that allows 5,000 Salvador guerrillas to keep fighting-- captures and purchases could not possibly provide it all; in the kinds of guerrilla arms captured by the Salvador army; in the numerous raw reports from the Salvadoran and Honduran armies of transit of supplies by burro, by planes landing on small strips or making drops, by the trucks that carry routine cargo through the region, by small boats on both Atlantic and Pacific coasts; in common sense.

Of course, the Nicaraguans help their friends--though how much is hard to pin down. Fidel Castro has admitted to foreigners a continuing hand, played through Nicaragua. Privately, the "comandantes" in Managua admit it to diplomats. On the record, the foreign minister admitted it to me; all he denied was that there is a "substantial" flow and that it is authorized. Why do we still claw each other on this?

In fact, there is reason to doubt the flow is unauthorized. Here we come, I think, to the core:

The Sandinistas spent the last Carter months pumping arms to the Salvador guerrillas, who hoped to present Reagan with an "irreversible" military situation. Jimmy Carter knew it but chose not to break off economic aid. The guerrilla "final offensive" failed. In came Reagan, who told Managua that if it did not stop the gun-running, he would stop the aid. Managua cut back promptly and sharply on the gun-running--American officials acknowledged it. Reagan responded . . . by halting economic aid.

The full story is not yet known. I strongly suspect, however, that this was the one moment when Ronald Reagan had a chance to break through the great apprehensions his election triggered in Managua. Whether by inattentiveness or something else, he blew it. Subsequent efforts to bridge the gap by talks seem to have faded into desultory contacts and angry words going nowhere.

The stakes are too high, it seems to me, not to keep trying. I have an idea, one arising from the palpable distrust one feels in Managua toward Reagan, Secretary of State Alexander Haig and Haig's deputy for Latin affairs, Thomas Enders, personally. The president should find somebody senior and savvy, with Latin experience, to make a new run. Then everyone should button his lip for a bit and give the special emissary a chance.

I think Reagan is right to take seriously Nicaragua's support of guerrillas in Salvador, and elsewhere--I will write next from Honduras. But his manner of seeming disrespect is costing him what little opportunity may remain to get a near-hysterical Nicaragua's attention to legitimate American interests. He must accept a requirement to convince the Sandinistas he is attentive to their legitimate interests. The strategic thrust of his policy is not misplaced. But it lacks the essential Latin touch.