THERE IS AN impression about that the Reagan administration has been unrelievedly belligerent and provocative toward Nicaragua and that this is why relations between the United States and the Sandinista regime have deteriorated. It is true that, off and on, the administration has spoken harshly and applied some hard (non-military) pressures, but that is not the sum of its policy.

In August, the Reagan administration made a still-veiled but reasonable offer of political coexistence to Nicaragua. The best evidence for so characterizing the offer is that some of the Sandinistas were attracted to it. A turn for the better seemed possible. Unfortunately, for reasons not yet elucidated, the promise of August soured. On the Nicaraguan side, this became evident in the Sandinistas' continued fueling of the guerrilla war in El Salvador, in the tightening of police controls at home and in an immense Soviet-Cuban-aided military buildup. It became evident on the American side in the application of fresh political and economic pressures on the Sandinistas, in new fears of a spillover into other countries of the region and in the raising of a full-throated alarm about "another Cuba."

Notwithstanding all this, the Reagan administration has shown a good deal more restraint than many of its press notices and its own pronouncements have indicated. With respect to military action, the administration is still in the stage of growling, not acting. The United States, Secretary of Defense Caspar Weinberger said Sunday, is "well away" from "drawing a line in the sand." Secretary of State Alexander Haig affirmed that the vista that this country tried to open in August is still available: a "full, normal and complementary" relationship in which American aid and cooperation would flow to "a pluralistic, democratic" Nicaragua. His words reflected President Reagan's pledge in his Nov. 18 foreign policy address to seek "the resolution of critical regional disputes at the conference table."

Something else needs underlining. The administration is consulting on Nicaragua, and on the companion problem of El Salvador, with its democratic friends in the hemisphere--last week with Venezuela, this week with Mexico. These countries strenuously oppose any American military intervention. They would like to see an American-Nicaraguan political understanding and, in their different ways, an American-Salvadoran political understanding. By consulting them, the administration yields a measure of its freedom to pursue an out-and-out military solution. But it gains a claim on their diplomacy. In particular, it gains a claim on Mexico to become more attentive to the free ride it has been giving Central America's Marxist left.

This is, we take it, what presidential counselor Edwin Meese III had in mind Sunday when he said that much of what the United States is doing "involves putting pressure on Nicaragua by other nations in the area." More such pressure evidently will come at the Organization of American States meeting in early December.

In brief, so far this administration has been much less the tiger than the tabby in dealing with Nicaragua. The other nations of the hemisphere, no less than American citizens, ought not to be confused about that. In its hemispheric policy, this administration is capable of being mean and silly--in refusing literally to answer the mail from tiny Grenada, for instance. With respect to Nicaragua it has often been insensitive to the anxieties that coexist with the ambitions and armaments that make the Sandinistas dangerous to their neighbors. But there is in the Reagan circle a strong desire to ease, by political and diplomatic means, the terrible tensions building in Central America. If the Sandinistas want a decent settlement, they can have one. The other nations of the hemisphere, most of all those sympathetic to the best impulses of the Nicaraguan revolution, have a duty to carry that word.