PRESIDENT CARTER probably had no choice last night but to put the best face on the terms offered by the Iranian parliament and to characterize them, as he did, as offering "a positive basis" on which to continue negotiating for the hostages' return. Yet it is important to remember that this is no routine international dispute. The people laying down the "conditions" to which the president is compelled to respond and who have manipulated and convulsed our whole political system are international terrorists who are holding a whole embassy for ransom. But the president could hardly be expected to announce, two days before an election, that his efforts to retrieve the 52 Americans had ground to at least a temporary halt in the political ruts of the Iranian Majlis.

The first of these conditions involves a no-interference commitment by the American government that should pose few problems. But the three other conditions, involving the unfreezing of Iranian assets, relief from American claims and return of the late shah's properties, are another story. They are certainly unacceptable as presented. It was precisely because of the difficulties posed by these demands, we presume, that President Carter felt it necessary last night to promise that he would not trifle with American laws and the Constitution, and that he would respect the national honor and integrity. That such assurances were required at all is evidence of the outrageousness of the Iranian position.

Clearly, the Iranians are trying to exploit the American people's presumed impatience and Mr. Carter's presumed electoral vulnerability. They would like Americans, and others, to overlook that it was by a hostile and illegal act of their own, the kidnapping of the embassy, that this situation was created. Now, a year later, they ask the United States to turn back the clock on the economic items and to make them whole for an injury that they, alone, did to themselves. The United States has its own good reasons -- human, political and strategic -- to make a deal, but this does not alter the root fact of the criminality of the Iranians.

Mr. Carter pledged that politics would play no part in his diplomacy. One does not have to suspect him of exploitation to understand the political overtones inherent in being seen to play a presidential crisis role. There are political overtones, too, of course, in Gov. Reagan's assuming of a stance of patriotic support of a crucial national enterprise. But these do not exhaust the larger political aspects. The Iranians, we suspect, by coming up after a year's time not with the hostages but with a set of troublesome demands, may have reminded a lot of Americans of the anger and humiliation they felt when the hostages were first seized. The result is likely to be a firm public insistence that the occupant of the White House, whoever he may be, reflect principle as well as compassion in negotiating for the hostages. That is the way it must be.