WASHINGTON — Legislation to extend unemployment subsidies for hundreds of thousands of Americans who have exhausted their jobless benefits teetered on the edge of collapse on Thursday, as Senate Democrats and Republicans traded bitter accusations about who was to blame for an eight-week impasse.

Senate Republicans and a lone Democrat, Ben Nelson of Nebraska, joined forces to filibuster the bill in a procedural vote on Thursday. Visibly frustrated, the majority leader, Harry Reid, Democrat of Nevada, said he would move on to other business next week because he saw little chance of winning over any Republican votes.

The vote was 57 to 41, with the Democrats falling three short of the 60 votes needed to advance the measure.

“You’ll hear a lot of excuses,” Mr. Reid said at a news conference. “The bottom line is the minority just said no.”