PRESIDENT CARTER is honoring his promise to inflict "increasingly heavy costs" upon Iran unless it frees the American hostages. He has just added another clutch of economic sanctions, including a request to Congress for authority to pay out frozen Iranian assets for reparations, commercial claims and crisis-related military costs. (As for his request to news media to minimize their presence and activities in Tehran, we think these matters should be guided, as they have been, by professional news standards.) If the economic and other measures taken by the allies don't work, Mr. Carter said, "the only next step available that I can see would be some sort of military action" -- the "sort" he indicated would involve interrupting Iran's commerce. Explicit tough talk like this is a departure for Mr. Carter but a necessary one, given Iran's rejection of the diplomatic path and the requirement that rejection created for him to switch to coercive tactics. Evidently he accepts the logic of his own policy.

The president's renewed call for "concerted action" from the allies comes as some of them are moving closer to economic and diplomatic sanctions. Portugal has announced a total trade embargo. What with the various pressures playing on the other Europeans, it would be surprising if they were to go that far. But the American objective is not and should not be go get them up to a certain line. It is to have them act in a way that removes doubt about whether they understand the American urgency. It is to alter the damaging perception that the countries closest to the United States shrink from supporting it on an issue -- the capture of diplomats -- on which it is 100 percent the injured party. Some of the allies act as though this requires them to commit national hari-kari. This is absurd. It requires them only to identify their self-interest. People in Europe and elsewhere who get fluttery at the mention of force should keep in mind that their own non-military moves are their best contribution to ensuring that force will not be employed.

The Iranians, though they show a fewsigns of nervousness (the to-do about visits to the hostages), otherwise are hanging tough. Their oil, the desire of some of them to cut Western links anyway, the availability of alternate links, and the exhilaration of confrontation are among the reasons. The pressure, however, is affecting the country's normal ways and cannot fail to sharpen its already-intense debate about the shape of its future. By mobilizing all the international pressure it can, the United States supports those in Iran who believe that its highest interest is to bring the hostage crisis to an end and to get on with other matters.