WASHINGTON – The fate of $600 to $1,200 rebate checks for more than 100 million Americans is in limbo after Senate Democrats failed Wednesday to add $44 billion in help for the elderly, disabled veterans, the unemployed and big business to the House-passed economic aid package.

Republicans banded together to block the $205 billion plan from advancing Wednesday, leaving Democrats with a difficult choice either to quickly accept a House bill they have said is inadequate or risk being blamed for delaying a measure designed as a swift shot in the arm for the lagging economy.

The tally was 58-41 to end debate on the Senate measure, just short of the 60 votes Democrats would have needed to scale procedural hurdles and move the bill to a final vote. In a suspenseful showdown vote that capped days of partisan infighting and procedural jockeying, eight Republicans joined Democrats to back the plan, bucking GOP leaders and President Bush, who objected to the costly add-ons.

“There was a chance on the table to help low-income seniors and disabled veterans and Americans looking for work, and the Senate frankly blew it tonight,” said Sen. Max Baucus, D-Mont.