IT IS NEARLY seven weeks since terrorists seized the American Embassy in Tehran and, despite everything, the fate of the hostages is still up in the air. As a result, you can hear people, even presidential loyalists, sighing and starting to ask whether Jimmy Carter's slow, non-violent turning of the screws is the right policy after all. Some people -- James Schlesinger, for instance -- go even further, suggesting now that the president would have done better to deliver an ultimatum at the outset. Impatience, if not on that order, is likely to grow, cutting into the general respect and tolerance for his policy that Mr. Carter has enjoyed so far and putting heat on him to produce results.

It is certainly true that this is a phase of deepening frustration. The easier steps in applying American pressure and mobilizing world support have been taken, and future increments, through graduated sanctions at the United Nations, for instance, will be hard to come by and cannot be expected to be decisive. Within Iran itself, the evident power struggle going on among the embassy terrorists, the ministers, the Revolutionary Council and the various ayatollahs -- to give an incomplete list -- had denied the United States the prerequisite of diplomatic progress: a constant and reliable source of authority with which to negotiate. Such limited readiness to compromise as has been visible has failed to stand up against the revolutionary tide of the militants actually holding the hostages.

As uncertain as the strategy of playing for time is, however, this in no time for going back. It leaves a great burden on the hostages, who, from the available reports, are showing awesome stamina and courage. But it is also putting a very great burden on Iran. While Ayatollah Khomeini and his fellow terrorists stage their despicable play, Iran is fragmenting along ethnic lines, the economy is suffering severe jolts and distortions, the revolution is shedding foreign and domestic sympathizers alike, the pro-communist left is gathering itself for an almost certain push against the ayatollah at a convenient time, and the country is becoming ever riper for Soviet penetration.

Some of these developments promise nothing but further trouble for American interests. But they are surely of more concern to Iranians. For the fact is that whatever damage the ayatollah and his followers believe the United States to have done to Iran over the past generation, it is small and shrinking next to the damage they are doing now. Jimmy Carter's strategy invites Iranians to make that choice.