PORT-AU-PRINCE, Haiti -- Most Clinton administration officials have concluded that new economic sanctions imposed against this nation will not work -- and only military intervention can drive Haiti's rulers from power, diplomats here and in Washington said. Diplomats here said they expect President Bill Clinton to give the sanctions several more weeks, then, at the end of July, to decide on military intervention. "When the troops move depends at this point entirely on politics and President Clinton's state of mind," one diplomat said. The main factor in the decision's timing, he added, is "to establish a wide enough window for Clinton to say the sanctions had enough time to work but failed." In Washington, a senior U.S. official involved in Haiti policy said that most administration experts believe the sanctions cannot succeed but a few still believe the economic measures could prompt the Haitian military to give up power peacefully. The issue is still being debated in the administration's inner councils, he said. "I don't think anybody says they," the sanctions, "will assuredly work," he said. "A few say they might -- and a lot say they can't." The official said the administration will keep imposing sanctions -- including a ban on commercial air flights and a freeze on international financial transfers announced only last week -- for two reasons: On the off-chance they may work, but also to convince Con-gress and other countries the administration tried every non-military option before turning to the use of force. The end of July decision date, which officials emphasize is not a deadline, coincides with a second major ingredient in U.S. strategy: The assembly of an international peacekeeping force to enter Haiti after the current military regime falls -- whether to a U.S. invasion or by peaceful means. "Once Clinton is assured that this," force "is in place, he will have only two options," a diplomat said, "to disengage and say only Haitians can solve Haiti's problems or to give the order to invade. As it stands, he'll give the order." Asked when the administration realized the newest sanctions would not oust the military regime that seized power from President Jean-Bertrand Aristide in 1991, a diplomat here answered: "There was never any doubt. Everyone knew from the beginning it wouldn't work." In an interview in Washington, Clinton's special envoy for Haiti, former Representative William H. Gray III, heatedly disputed that view. "We believe these sanctions can work, just as sanctions worked in South Africa, once the coup leaders see that we are serious about enforcing them," he said."Most of these sanctions have been in effect for less than four weeks," he added. "Before May 21," when the UN Security Council imposed a ban on most trade with Haiti, "you didn't have any real sanctions. So it's too early to tell what the substantive impact is. ... But already, we have seen some people rush to get out of Haiti and others rush to ship money and packages to their families in Haiti. So they are having both a physical and psychological impact." Gray noted that Clinton has not ruled out military action but said the president has decided to make a serious attempt to enforce the sanctions first. "There is no disagreement on the policy at this level." But at lower levels, many U.S. officials are skeptical. "There is absolutely no sign that the military will give up," said one official in Port-au-Prince. "In fact, they are hardening their position. "Most don't believe there will be an intervention," he said. "They don't think Clinton has the guts or the political support to do it. But if it does happen, they have plans to make it so messy that he won't stay." Another American official said the U.S. Embassy in Port-au-Prince, including Ambassador William L. Swing, is uninvolved in policy planning and has been ordered to simply parrot the administration's public stand that the sanctions will work.But most Clinton advisers "have been operating on this assumption," of the need for military action, "for several weeks, well before the new sanctions were ordered," one diplomat here said. The Americans "knew from the beginning that cutting off air service and stopping financial dealings wouldn't work," another diplomat here said. "That was done because Clinton insists on operating with at least the appearance of international support." To get that backing and to offset U.S. congressional opposition, he said, Clinton "felt he had to use every last alternative, even though the administration's Haiti experts all advised that the new sanctions would not drive the military out."