Leading Senate Democrats vowed today to use their new majority in Congress to press for troop reductions in Iraq within a matter of months, stepping up pressure on the administration just as President Bush is to be interviewed by a bipartisan panel examining future strategy for the war. The Democrats ? the incoming majority leader, Senator Harry Reid; the incoming Armed Services Committee chairman, Senator Carl Levin; and the incoming Foreign Relations Committee chairman, Senator Joseph R. Biden Jr. ? said a phased redeployment of troops would be their top priority when the new Congress convenes in January, even before...