THE RELEASE of one American hostage, from a hospital in Tehran, is being presented by Ayatollah Khomeini as a benefaction flowing from the innately humanitarian content of Islam. Not everyone will be inclined to put the same judgment on it, but never mind. It is good to have it underlined, especially by the ayatollah, that a humanitarian component is central to the hostages' situation. On that basis, an overwhelming argument can be made for the immediate release of the remaining hostages, even if -- as we hope -- they are not ill: they have been held now, in conditions of extreme duress, for more than 250 days. It is good too, to have it demonstrated that there is at, least one party in Iran with the authority to break through the internal political stalemate responsible for the hostages' continued captivity, and to start the process of freeing them.

As much by default as design, a consensus on the hostages has taken hold in Washington since the aborted resuce effort. It replaces activism with patience, counting on the play of Iranian politics, sense, time and distraction -- and the sanctions already in place -- to work the result that earlier policy had failed to bring about. The theory has been that the Iranian price for the hostages would go down if the United States controlled its anger and showed itself unwilling to yield and ready to wait the crisis out. The only notable exception to the accompanying tactic of verbal restraint has come in the sharp criticism that Jimmy Carter leveled against the Iranian leadership in a campaign appearance on the Fourth of July. About this new policy not much can be said beyond the evident fact that, like its predecessor, it has not yet been seen to work. It imposes a difficult discretion upon Americans, but no alternative to it is evident.

One fresh if faint possibility is raised, however, by the release of the first hostage. Though this could be a one-shot affair designed to spare the Iranians the embarrassment of a medical emergency, it could also be a test of the internal and foreign waters to see what the various reactions will be. Even if this latter purpose is not what the Iranians originally had in mind, little is lost by treating it that way. Ayatollah Khomeini should be encouraged to continue demonstrating the grace of Islam -- by releasing his remaining prisoners.