AFTER months of indecision and differences with its Western European allies and the United Nations, the United States appears to have firmed up its thinking on the settlement of the Yugoslav crisis.
One major refinement is Washington's decision to join its European partners and Russia in backing a plan for the partition of Bosnia-Herzegovina, with 51 percent of the republic going to the new Muslim-Croat federation.
The plan, which would require the Bosnian Serbs to relinquish almost one-quarter of the territory they have seized, is being considered in political negotiations held simultaneously with cease-fire talks in Geneva.
Western diplomatic sources say the specifics of the undisclosed plan were developed in pre-Geneva consultations between US special envoy to former Yugoslavia Charles Redman and other mediators in the ``contact group'' on Bosnia.
The group was recently formed by the US, Britian, France, Russia, and the UN to reconcile conflicting approaches to ending the Bosnian war.
And a senior US official has suggested specific outlines for a peace accord between Croatia and the Belgrade-backed minority Serb rebels who overran the Krajina region in a seven-month war in 1991 and declared independence.
The US Ambassador to Croatia Peter Galbraith, speaking at Zagreb University June 2, reiterated that Krajina must be reincorporated into Croatia, and that ``not a single member'' of the UN would ever recognize its independence.
But he added that Croatian President Franjo Tudjman's nationalist regime would have to make broad concessions to the Krajina Serbs, including granting ``substantial autonomy'' to the areas where they made up prewar majorities.
``It would certainly mean the right to have an elected legislature, control education, raise money for taxes, control police, and all functions of local, or state, governments...,'' he said, adding that the Serbs should even be allowed their own flag.
He concluded by urging Croatian leaders and people ``to do everything possible to make Croatia an acceptable and even desirable place for Serbs to live.''
Mr. Galbraith asserted that his was not ``an American formula.'' But his speech elaborated on previous ideas for an accord and represented official US thinking in that he is the chief US negotiator in a US-Russian-UN effort to resolve the Krajina issue.
But the refinements in the US stands on Croatia and Bosnia by no means signify that political resolutions are any closer. The Bosnian Serbs remain unwilling to make serious territorial concessions. They are still intent on winning an independent state that could eventually unite with the Serb-dominated rump Yugoslav union of Serbia and Montenegro.
For their parts, leaders of Bosnia's new Muslim-Croat federation want a 58-42 percent territorial split and oppose the creation of an independent Bosnian Serb state. Muslim leaders have also not given up their hopes of recapturing Bosnian Serb-held territory by military force.
Meanwhile, negotiations between Croatia and the Krajina Serbs have been suspended since May 26 because of a total lack of progress following the implementation of a UN-monitored cease-fire accord in April.
The Krajina Serbs, who are held chiefly responsible for the impasse, continue to reject any reintegration with Croatia.
The Tudjman regime has now begun threatening not to renew the UN peacekeeping mandate that expires on Sept. 30 and to resort to force to ``liberate'' the Krajina in a new war.
While political resolutions remain as elusive as ever, Western diplomats say the refinements in US thinking should ease frictions between the US, its European allies, and the UN, produced by differences over Yugoslav policy, principally on Bosnia.
Among other things, Washington's refusal to pressure the Muslim-led Bosnian government to accept a peace deal was seen by Western European and UN officials as encouraging the Bosnian Army to continue its uphill fight against the Bosnian Serbs.
Yasushi Akashi, head of the UN Protection Force (UNPROFOR), enraged Washington by condemning its conduct as ``somewhat reticent, somewhat afraid, timid, and tentative.'' Washington initially declined to endorse a specific territorial division because of sympathy for the Muslims and a view that the Bosnian Serbs, backed militarily and financially by Serbia, are the aggressors.
In brokering in February the end to almost a year of fighting between the Bosnian Croats and Muslims and the formation of their new federation, the US backed the 58-42 percent partition. Now it has climbed aboard the European Union 51-49 plan.
Washington favors an exemption for the Bosnian government from the UN arms embargo on former Yugoslavia and a more aggressive use of military might to ensure Bosnian Serb compliance with UN resolutions. The EU, UN, and Moscow oppose both.
For their parts, EU and UN officials are angered by President Clinton's refusal to contribute US troops to UNPROFOR.