WASHINGTON — PRESIDENT Clinton's use of air power and aggressive diplomacy to force an end to more than three years of bloodletting in Bosnia-Herzegovina has bought him badly needed breathing room on Capitol Hill - but not much.
Congressional support is strong for Mr. Clinton's more assertive policy in Bosnia. But most lawmakers appear unwilling to delay for much longer a vote to override his veto of legislation that would compel the United States to unilaterally exempt the Muslim-led Bosnian government from a UN arms embargo.
Informed congressional sources say Senate majority leader Bob Dole (R) of Kansas has tentatively scheduled the override vote for next week.
''The Clinton administration has to produce results fast, not just produce results. The patience level is so low,'' says a Republican congressional aide.
Even if Clinton's strategy of bombs and bargaining pays off, the embargo will still have to be lifted, supporters of the legislation say. They explain that a lasting peace will require a balance of military power between the Bosnian government and Bosnian Serb forces.
''There is not going to be a stable peace unless there is a balance of power on the ground,'' says Sen. Joseph Lieberman (D) of Connecticut who co-sponsored the legislation to lift the embargo with Senator Dole.
Elaborates a congressional source: ''If you leave the Bosnian government in a weak position and the [Bosnian] Serbs in a strong position, you won't come up with an enduring solution.''
In an embarrassing repudiation of Clinton's Bosnia policy, the House and Senate voted last summer by huge margins to lift the embargo, which was imposed on all the former Yugoslav republics in 1991.
The measure would require Clinton to end US participation in the embargo after UN peacekeepers are withdrawn or 12 weeks after the Bosnian government requests their departure.
Proponents of the measure argue that Bosnia has a moral and legal right to defend itself against the Bosnian Serb rebels, who are armed by neighboring Serbia.
Clinton vetoed the measure on Aug. 11, arguing that it would divide NATO, widen the Bosnian war, and force the withdrawal of UN peacekeeping forces.
Saying he was willing to give Clinton's forceful new policy in Bosnia a chance to succeed, Dole agreed last week to delay an override attempt in the Senate that was scheduled for this week.
''Obviously, by saying that we are considering delaying the vote it was a kind of carrot and stick to Clinton,'' says the GOP source. ''What we're saying is, keep going on the airstrikes.''
Responding to an Aug. 28 artillery attack that killed at least 28 civilians in Sarajevo, Clinton won the backing of the Western European allies for a sustained campaign of NATO airstrikes against Bosnia Serb military targets. One objective was to break the siege of the Bosnian capital.
A second objective was to force the Bosnian Serbs to cooperate with a new US-led peace effort. A plan carried to the region by Assistant Secretary of State Richard Holbrooke would partition Bosnia into ethnic zones within a unitary state. The foreign ministers of Bosnia, Serbia, and Croatia will gather in Geneva today to discuss the initiative.
Clinton's initial success could convince as many as six moderate Democrats who voted to lift the embargo to withhold their support for a veto override, which requires a two-thirds vote.
But even if Clinton manages to avert an override, Congress will almost certainly have more to say about his Bosnia policy. Dole has already warned the administration against brokering a peace that, in his words, ''merely ratifies Serb gains made through aggression and ethnic cleansing.''
Congressional sources say the US plan calls for the deployment of American troops as part of an international contingent that would guarantee a final settlement.
Lawmakers could refuse to fund the US troop deployment if they are unhappy with the settlement. Their support could also hinge on whether US troops would have to participate in population transfers between the proposed ethnic zones.
''There are different points of leverage,'' says Senator Lieberman. ''The administration needs to get the support of the Congress for the money and in some sense for the whole idea of American participation in the peacekeeping force. It's going to be hard enough to get that support but very hard if there is a sense that the Bosnians are getting a raw deal.''
Congress could also reduce or withhold economic reconstruction aid to Bosnia or Serbia that Holbrooke says is part of the US plan.