The 53-45 vote was seven votes short of the 60 needed to advance. It came minutes after the Senate rejected a Republican proposal to pay for the Iraq war without strings attached.
The Republican measure failed 45-53, 15 short of the number of votes needed to go forward.
The bottom line, reports CBS News correspondent Bob Fuss, is that there will be no additional money for the Iraq war for now, and probably not until late January.
Democrats are adamant they won't just keep giving President Bush everything he asks for to continue a war they want to stop. Defense Secretary Robert Gates has publicly warned that he'll have to start closing bases and firing people, but Democratic leaders said Gates told them privately there's enough money in the hopper to last until February.
Senate Majority Leader Harry Reid said the only way to get troops the money was to approve the restrictions outlined by Democrats.
"Our troops continue to fight and die valiantly. And our Treasury continues to be depleted rapidly, for a peace that we seem far more interested in achieving than Iraq's own political leaders," said Reid, D-Nev.
Republicans said Democrats were being irresponsible.
"We need to get our troops everything they need," said Senate Republican Leader Mitch McConnell, R-Ky. "We need to get it to them right now."
Reid and House Speaker Nancy Pelosi, D-Calif., said this week that if Congress cannot pass legislation that ties war money to troop withdrawals, they would not send Mr. Bush a bill this year.
Instead, they would revisit the issue upon returning in January, pushing the Pentagon to the brink of an accounting nightmare and deepening Democrats' conflict with the White House on the war.
In the meantime, Democrats say, the Pentagon can eat into its $471 billion annual budget without being forced to take drastic steps.
"The days of a free lunch are over," said Sen. Chuck Schumer, D-N.Y.
At the White House Friday, deputy press secretary Tony Fratto said: "DOD would have to eat into their annual budget and I believe that still presents difficulties in getting the troops in the field the resources they need to carry out their mission."
"We'd rather see the Department of Defense, the military planners and our troops focusing on military maneuvers, rather than accounting maneuvers as they carry out their mission in the field," Fratto said. "I think Congress should send this money, allow these troops to get the equipment they need. There is no reason why they should not get the money. This isn't like this is a last-minute effort and call for funding."
Gates said Thursday that unless Congress passes funding for the war within days, he will direct the Army and Marine Corps to begin developing plans to lay off employees and terminate contracts early next year.
The defense secretary, who met with lawmakers on Wednesday, said he does not have the money or the flexibility to move funds around to adequately cover the costs of the continuing operations in Iraq and Afghanistan.
"There is a misperception that this department can continue funding our troops in the field for an indefinite period of time through accounting maneuvers, that we can shuffle money around the department. This is a serious misconception," Gates told reporters at the Pentagon.
As a result, he said he is faced with the undesirable task of preparing to cease operations at Army bases by mid-February, and lay off about 100,000 defense department employees and an equal number of civilian contractors. A month later, he said, similar moves would have to be made by the Marines.
Some members of Congress believe the Pentagon can switch enough money to cover the war accounts, Gates said. But he added that he only has the flexibility to transfer about $3.7 billion, which is just one week's worth of war expenses. Lawmakers, he said, may not understand how complicated and restrictive the situation is.