Defying President Clinton and the international community, Senate Republicans this evening neared passage of a vote to lift the U.S. arms embargo on Bosnia. The move, approved in the House earlier this year, would be an affront to Clinton and the U.N. Security Council, which imposedthe arms embargoon the former Yugoslavia in 1991, hoping to prevent an escalation ofthe fighting in the Balkans. Senate Majority LeaderBob Dole, who at Clinton's request delayed action last week to await the results of the NATO allies conference in London, argued on the Senate floor that the embargo merely established a built-in military advantage for rebel Bosnian Serb forces. "We have an obligation to the Bosnian people and to our principles to allow a U.N. member state, the victim of aggression, to defend itself," he said. Clinton, clearly frustrated, fired off a letter to Senate Republicans warning of a potential U.S. quagmire: "Unilateral lift means unilateral responsibility," he wrote. "Congress would undermine efforts to achieve a negotiated settlement in Bosnia and could lead to an escalation of the conflict there." France and Britain have threatened to withdraw their peacekeepers from Bosnia if the U.S. lifts the embargo, and Clinton has promised 25,000 ground troops to help with that evacuation. "Consequently, at the least," Clinton wrote, "unilateral lift by the U.S. drives our European allies out and pulls the U.S. in."