A SCENE the Clinton administration officials say they have long tried to avoid may soon be flashing across American TV screens -- tens of thousands of United States troops risking their lives in the former Yugoslavia.
The former Yugoslav republic of Croatia is demanding the withdrawal by June 30 of 14,000 United Nations peacekeepers who have been separating its Army from minority rebel Serbs for three years. If it happens, the pullout would be protected by a NATO force that would almost certainly include a large number of US soldiers.
''It's very hard for me to imagine the United States not participating with NATO in such an operation,'' says Gen. John Shalikashvili, the chairman of the Joint Chiefs of Staff.
Defense Secretary William Perry and his counterparts from Britain, France, and Germany spent the weekend in Key West, Fla., discussing NATO planning for Croatia.
Senior US officials say that a decision on contributing troops to a NATO operation in Croatia depends on a review of the final plans and consultations with Congress. But General Shalikashvili made it clear that he believes there must be US participation.
''The solidarity of the [NATO] alliance and keeping the trans-Atlantic linkage together are, in my judgment, overriding issues,'' Shalikashvili says. He says he expects NATO to complete its planning for Croatia by the middle of this month.
To avert that risk-fraught scenario, the White House is pursuing an 11th-hour diplomatic scramble to pressure Croatian President Franjo Tudjman into allowing some kind of UN peacekeeping force to remain in Croatia.
US flexes diplomatic muscle
The effort is being led by Assistant Secretary of State Richard Holbrooke, who was to meet today in Zagreb, Croatia, with President Tudjman.
US and UN officials say that Mr. Holbrooke will warn Tudjman that Croatia will face punitive Western measures unless he reconsiders his demand for the departure of the UN Protection Force (UNPROFOR).
''Our message will be very strong,'' a US diplomatic source says.
The source declined to elaborate. But he noted that US Ambassador to Croatia Peter Galbraith has been warning publicly for months that Croatia would lose newly won Western economic and political support if it did anything that could reignite fighting with the rebel Serbs.
''It would not be unreasonable to conclude that this is the message that Holbrooke will bring to Zagreb,'' the source says.
He adds that Holbrooke will also tell Tudjman that he will not get any Western help should the Croatian Army find itself in trouble in any renewed fighting with the Krajina Serbs.
Tudjman, responding to growing domestic political pressure, announced to public acclaim in January that he would not renew UNPROFOR's mandate when it expires on March 1.
Too late for a compromise?
UNPROFOR is unpopular among Croats because it failed to implement a 1991 accord mandating the disarming of the Serb rebels who seized about one-third of Croatia -- known as the Krajina -- with the help of the Serb-dominated Yugoslav Army. The Serb rebels want to unite their territory with Serbia and Serb-held areas of Bosnia.
Holbrooke was expected to press Tudjman to accept a compromise plan that would slash UNPROFOR to 6,000 troops, but maintain them in front-line buffer positions.
It would also allow UN forces in Bosnia to maintain their headquarters and logistics operations in Croatia. Without those operations, the UN might be forced to leave Bosnia as well.
Tudjman has already rejected the compromise plan. Instead, he has suggested that UNPROFOR be replaced by troops from the United States, Britain, France, Germany, and Russia. The five make up the ''contact group.''
Unless Tudjman can be pressured to drop his demand for a UN withdrawal, UN and Western officials envision a massive NATO operation, involving as many as 40,000 troops and air power, to protect the UN withdrawal.
They are concerned that departing UN soldiers could be trapped between Croatian and Serb fighters battling for abandoned UN positions. UN personnel could also be taken hostage and used as human shields.
A senior UN military official says UNPROFOR will disclose its withdrawal plans in advance to both sides in hopes of averting chaos and uncertainty. ''It's going to be very deliberate, very transparent,'' the official says.
''We are going to be quite up front with both sides to the point where we'll be giving our plans to all the sides involved. We don't want to surprise people,'' he adds.
The Clinton administration has not yet agreed to contribute US troops to a NATO protection operation in Croatia. But the chances are high that it will as it consented last year to providing up to 12,000 troops to protect any UN withdrawal from Bosnia.
But other officials on the ground in Croatia caution that a double Croatia and Bosnia UN pullout scenario is unlikely to happen. They say such doomsday scenarios are attempts by Western diplomats to pressure Tudjman to allow the UN to stay before their mandate expires on March 31. They predict this minicrisis in the war will stretch on as so many others have in the three-year-old war.
''Deadlines in the Balkans tend to be very loose and can be reinstated,'' a UN military official says. ''We've been through this before.''