Despite a House vote Thursday to lift the Bosnia arms embargo and a personal plea from the Bosnian prime minister in Washington today, the White House said President Clinton would promptly veto the measure if it reached his desk. "We don't believe the answer to the conflict in Bosnia is to escalate the war," said White House spokesman Mike McCurry. The Administration believes that lifting the embargo would anger France, Britain and other countries with peacekeeping troops in the region, andtrigger a commitment of 25,000 American troopsto helpevacuate the peacekeepersand protect the Muslims from a predicted new Serbian assault. (If European peacekeepers withdraw, however, McCurry said, "it may well be that lifting the arms embargo proves unavoidable as a last resort.") A bipartisan chorus of senators, meanwhile, predicted that the full Senate would nonetheless follow the House lead. Said Senate Minority Leader Tom Daschle (D-S.D.): "At least Bosnians ought to have an opportunity to arm themselves, to defend themselves. We may not be left with any other choice."