PRESIDENT Clinton's veto of a congressional resolution to end American participation in an arms embargo against Bosnia preserves his diplomatic options in the former Yugoslavia, but at a potentially high political price.
The veto buys time for the United States and its Western allies to capitalize on a slim new opportunity - and perhaps the last one - to reach a negotiated end to four years of intense fighting between the Bosnian government and rebel Serb forces.
But if Mr. Clinton's veto is overridden - a better than even possibility, many congressional observers say - he would sustain a crucial foreign-policy defeat going into the 1996 election season.
"It would be the most decisive defeat of Clinton's presidency on a foreign-policy issue," notes a congressional source about the veto, which was announced by the White House on Friday.
The resolution to lift the arms embargo was approved late last month by the Senate and early this month by the House, both with lopsided majorities. The votes reflected a deepening dissatisfaction with the administration's handling of the Bosnia crisis and waning confidence in the prospect of a negotiated settlement.
Sponsors of the measure, led by Senate majority leader Bob Dole (R) of Kansas, argue that lifting the arms embargo would level the playing field by enabling the Bosnian government to fight on more equal terms against heavily armed Serb forces who now control 70 percent of Bosnia.
Administration officials worry that lifting the embargo will trigger the evacuation of UN peacekeeping forces, weaken NATO unity, and widen and intensify a brutal war that has already claimed tens of thousands of lives.
Under the terms of the House and Senate resolutions, Clinton would be obliged to end US participation in the embargo after UN peacekeepers are withdrawn, or within 12 weeks after the Bosnian government requests their departure and the lifting of the embargo.
"The embargo doesn't compromise the Bosnian government's control over its own destiny," insists one Republican source in the Senate. "If it chooses to put hope into the process, that's terrific."
It is in the context of just such a hope that Clinton chose to cast the second veto of his presidency.
Administration officials say last week's dramatic expulsion by Croatian troops of 150,000 ethnic Serbs from the Krajina region of Croatia could, by puncturing the myth of Serbian invincibility, persuade Bosnian Serb leaders to reconsider their rejection of a 1994 Western peace plan. The plan calls for dividing Bosnia roughly in half; 51 percent would go to the federation of Muslims and Croats, and 49 percent to the Serbs.
Eager to seize the moment, Clinton sent two top foreign-policy advisers - National Security Adviser Anthony Lake and Undersecretary of State Peter Tarnoff - to Europe Wednesday to discuss new ideas for breathing life into the moribund peace process.
The administration remains nominally committed to the idea of a multiethnic Bosnian confederation.
But reflecting new circumstances on the ground - including the takeover by Serbian forces this summer of two UN-designated "safe havens" in eastern Bosnia - administration officials are now said to favor arrangements that would have the effect of dividing Bosnia permanently along ethnic lines.
Clinton is eager to defuse the Bosnia crisis before the onset of election season, during which Republicans will almost certainly accuse him of drift and vacillation in dealing with the Bosnian crisis.
Bosnia could prove an even greater liability for Clinton if, in the absence of a political settlement, he is obliged during an election year to fulfill a promise to dispatch up to 25,000 US troops to facilitate the departure of UN peacekeeping forces.
The US has warned Croatia that if it presses the military advantage by attacking Serb positions in eastern Croatia, the result could be a wider war rather than a new opportunity for peace.
Serbia has dispatched tanks and artillery to the Croatian border to prepare for an attack. Croatian officials have said that they will not move against Eastern Slavonia, an oil-rich region once populated by 100,000 Croats that was taken in 1991 by Serb forces.
The victory of Croatian arms in the Krajina could pose other threats to a peaceful settlement in Bosnia. Serbs expelled from the Krajina could be incorporated into the Bosnian Serb army, putting more pressure on Bosnia. Conversely, last week's defeat of Croatia's Serbs could embolden Bosnia to reject any new Western peace proposal.
Mr. Dole and five Senate colleagues last week introduced legislation that would provide $100 million in military assistance to help the Bosnian government prosecute its war against Serb forces after the embargo is lifted.
The embargo resolution was passed by veto-proof margins in both Houses. Whether two-thirds plus majorities can be preserved in the House and Senate will depend on developments in Bosnia during Congress's three-week summer recess.
"If things seem to be stabilizing on the ground, that will contribute to Clinton's position," says the first congressional source. "But if you have a reassertion of the Serbian position, that increases the likelihood that it would be overturned."