WASHINGTON -- The Clinton administration is hoping to persuade the Western allies to support a new carve-up of Bosnia that would technically preserve the nation's existence but effectively divide it between neighbors Croatia and Serbia, U.S. officials and Western diplomats have said.


The U.S. ideas, designed to take advantage of the political momentum created by Croatia's victory over Serb rebels, will be presented by National Security Adviser Anthony Lake to European officials this week. They include suggestions for changes to a June 1994 proposal by international mediators on how to divide Bosnia among Serbs, Moslems and Croats.


A senior official said European leaders raised many objections to the suggestions in telephone discussions with President Bill Clinton this week, and the administration was not optimistic that a broad agreement could be reached easily.


"Frankly, we don't think this has all that much chance of succeeding,'' the official said. But the official added, "We have to try something,'' because pressures are rising both from Congress and from the Europeans, who want a decision by early fall on whether to withdraw their peacekeepers.


U.S. officials said the latest American proposal is aimed at obtaining a comprehensive peace settlement among Bosnia, Croatia, and the Yugoslav federation of Serbia and Montenegro. U.S. and European negotiators have been working on a deal to persuade Serbian President Slobodan Milosevic to recognize Bosnia, and possibly Croatia, in return for an easing of United Nations sanctions.


A State Department official described the Lake proposals as "an inventory of ideas, rather than a firm U.S. position.'' Other officials said prospects for peace appeared to have been significantly improved by the Croatian victory in the breakaway region of Krajina, which has had the effect of smashing the myth of Serb invincibility.


The new U.S. proposals could result in the abandonment of Gorazde, the sole remaining UN-protected "safe area'' in eastern Bosnia. In return, the Bosnian government would acquire territory around Sarajevo, giving it easier access to the capital and a more consolidated mini-state. A NATO pledge to use air power to forestall any attack on Gorazde would effectively lapse. The existing plan, originally presented as a take-it-or-leave-it offer by the mediators in the Contact Group, awards 51 percent of Bosnia to the Moslem-Croat federation and 49 percent to the Bosnian Serbs. Thanks to their big gains in the early stages of the war, the Serbs now control roughly 70 percent of Bosnian territory.


While the new U.S. ideas would involve significant changes to the Contact Group map, the extent to which the Serbs could hang on to their existing gains was unclear. A State Department official insisted that the Moslem-Croat share would not be allowed to drop below 50 percent, but another, senior official raised the possibility of the Bosnian Moslems being pressured to accept much less land than what is outlined in the Contact Group map. The latter official said the Moslems would have to accept a settlement that reflected "the military reality, not wishful thinking.''


The new U.S. proposals would permit the Bosnian Serbs to confederate with Serbia, and the Moslem-Croat portion to confederate with Croatia. The result of such an arrangement would be to divide the landlocked republic between its two more-powerful neighbors, although the figleaf of a very loose Bosnian state would still be preserved.


Some U.S. officials would like to encourage the Serbs to come to the negotiating table by holding out the threat of withdrawing the UN peacekeeping force, arming the Moslems, and using U.S. air power against the Serbs. The Europeans, who still have peacekeepers on the ground in Bosnia, have made clear they would oppose such a threat.


Another U.S. idea is for the Europeans and the United States to assemble a coalition peacekeeping force made up primarily of soldiers from Islamic nations if Britain and France insist on removing their troops.