THE last of America's hostages in the Middle East is free. For that we can thank God, the secretary-general of the United Nations, the determination of the Bush administration not to deal with terrorists, and - not least - the grit and spirit of the hostages themselves. They are surely classic examples of the strength of the human spirit. If anyone has "won" in this sordid business, they have.And, yes, we can "thank" the Iranians. But not for any generosity on their part - only for doing what they should have done long ago. They deserve a nod simply for finally coming to an appreciation that if Iran's revolution is ever to produce tangible economic benefits for its people, it needs to clean up its act on the world stage. President Hashemi Rafsanjani is no fool, nor is he a moderate, but he is a pragmatist - and knows that money used to pay off the Hezbollah in Beirut (for surely that was a cr itical item in the hostages' release) will be worth it in the larger picture of Iran's need for Western eco-nomic, trade, and credit support. But we need to be realistic about any talk of a "warming" in an Iranian-American relationship. A decade and more of anti-American vitriol has left plenty of political sentiment that the revolution's radicals can exploit - as former Chief Justice (and Ayatollah) Musavi Ardebeli did two weeks ago, during Friday Prayers in Tehran, in calling on Muslims worldwide to continue a guerrilla war against American diplomats and others. Or as another leading radical (and mentor of the Hezbollah in Lebanon), Ali Akba r Mohtashemi, did in a Newsweek interview, terming George Bush a criminal whose "blood is of no further value." Mr. Rafsanjani can cite some success in gaining an upper hand over radical political contenders of this variety. He can also claim, as he did in his recent address to the Group of 77 conclave in Tehran, that a fundamental precept of Iran's foreign policy is "respect for the social and religious values of other peoples." But the rest of the world will believe that only when the execution order for Salman Rushdie is rescinded, and when the regime's record on human rights at home begins to meet even the min imal standards of outside observers such as Amnesty International. Iran is a country of consequence in the Middle East, and especially in the Persian Gulf. Its oil reserves, its 55 million people, and its command of much of the shore of the Gulf give it, potentially at least, no small clout. There can be no long-term security arrangement in the Gulf without its neighbors (and the United States) taking that fact into account. However, the present regime's ambitions to have paramount influence in the region are probably no less than that of the Shah - and the potential fo r friction with places like Baghdad and Riyadh is no less either, and probably greater. Moreover, the Rafsanjani government's opposition to an American presence in the Gulf, though muted in the aftermath of Desert Storm, is still dogma, and that in itself will remain a limitation for any significant "warming" in Iran's relationship with the US. All of which should dictate patience and hardheaded realism in policy toward Tehran, letting the initiatives come from them. Or, as President Bush has put it, let good will beget good will. We should have a relationship, and someday we can and will. But there is no compelling need for it now from our side - not until that regime demonstrates that it is open to one and wants one. And it is highly unlikely that that will be apparent until after the parliamentary elections scheduled for next spring, if at a ll. Meanwhile, those commercial contacts that are slowly beginning to expand and the ongoing claims settlement process at The Hague provide areas where Rafsanjani can, if he chooses, demonstrate more of his pragmatism - and in so doing contribute to the confidence building essential if there is to be even the beginning of the mutual trust needed for a meaningful "warming."