The Senate rejected the resolution 50-48 after agreeing that 60 votes would be required to pass it, The New York Times reported.
The vote was along party lines. Only one Republican, Gordon Smith of Oregon, voted for it and two Democrats, Mark Pryor of Arkansas and Ben Nelson of Nebraska, joined Independent Democrat Joseph Lieberman of Connecticut in opposing it.
Also Thursday, in another party-line vote, the House Appropriations Committee voted 36-28 to approve a $124 billion emergency spending bill that includes the troop withdrawal deadline. Under the Democratic plan, most troops would have to be out of Iraq by Aug. 31, 2008.
The appropriations bill includes money for operations in Afghanistan and Iraq as well as millions of dollars for domestic programs. Republicans accused the Democratic majority of loading the measure to increase the chance of passage.
Democrats emphasized that they are not cutting off funding for the military.
"Is there anyone who thinks we shouldn't have equipment here or training for the troops?" asked Rep. John P. Murtha, D-Pa.