By a vote of 60 to 36, the Senate voted to keep the measure within the $106 billion war funding bill it passed today, according to Reuters. The full bill, which the House of Representatives passed Tuesday, now moves to the president's desk.
The "cash for clunkers" program would allow consumers to trade in their old cars for a voucher of up to $4,500 when buying a new, more fuel-efficient vehicle.
Sen. Judd Gregg (R-N.H.) objected to the measure because it did not call for budget cuts elsewhere in order to pay for the program.
"There are innumerable places in this government, which is spending trillions of dollars a year, to find $1 billion to pay for this bill if it was a priority," Gregg said during the floor debate, Reuters reported.
Democrats said the measure was important because of the recent sharp decline in auto sales.
"Plummeting auto sales have reduced production and it's had a ripple effect across the economy, forcing dealerships and factories to close," said Democratic Sen. Richard Durbin (D-Ill.) said.
"Cash for clunkers" could spur immediate car purchases, some economists told CBSNews.com last month, but it might not have much of an impact in reducing carbon emissions, as claimed by Democrats. Furthermore, they said, it could have been crafted in a manner less burdensome for taxpayers.
"Cash-for-clunkers is a common sense proposal that will help provide a shot in the arm for the American auto industry at a crucial time for our economy, reduce the emissions that cause climate change, and make Americans more energy independent," House Speaker Nancy Pelosi (D-Calif.) said in a statement last month.