The nation’s anguish over the Iraq war was kept on hold in the Senate yesterday as the Republican minority maintained serial threats of filibuster to buy time for President Bush’s aimless policies. Last week, the House debated and voted along party lines for a timetable for an American troop withdrawal by next spring. But a similar measure was allowed no such decisive expression in the Senate. Instead, the G.O.P. insisted on the approval of a “supermajority” of 60 of 100 senators before putting to a vote a measure that would apply real pressure on the president to shift his disastrous...