Manchin had backed Collins' proposal, which would have funded the government at current levels for six months and raised the debt limit through the end of January. It would have required the House and Senate to enter broader budget negotiations but left in place the deep across-the-board cuts known as the sequester while they talked.
An aide said other Democrats, who had opposed Collins' proposal because it would have left the sequester untouched, had been growing annoyed with their own leadership late Friday and Saturday morning, as rumors spread that a deal was being forged around its tenets before they had been briefed about it.
"The key to this place is communication, even if there's nothing to say," the Democratic aide said. "If members feel like they're being kept out of the loop, they get upset."
Likewise, in the House, Rep. Scott Rigell, R-Va., had a raised-voice hallway confrontation with a member of his leadership in clear view of reporters, demanding to know how House leaders plan to resolve the stalemate.
"If Eric Cantor and John Boehner can't answer the questions 'what are we fighting for' -- that's not good!" Rigell told Rep. Cathy McMorris Rodgers of Washington, the House's fourth-ranking Republican.
Rigell has been one of the leading Republican voices urging the GOP to pass a measure to reopen the government, even without getting significant changes to the Affordable Care Act in return.
"We're on the same page, but we need to be able to articulate specific objectives," he continued, jabbing his finger in the air to make the point, before an aide came over to suggest that the two continue the conversation in private.
But the low point of the day came when a spokesman for House Majority Leader Eric Cantor, R-Va., accused Rep. Joseph Crowley, D-N.Y., of having a physical altercation with another Cantor aide on the House floor.
Crowley denied touching the aide during the incident, which came after Republicans shut down an attempt by Democrats to lodge repeated requests for the chamber to consider a bill to reopen the government without any conditions.
"He had come to our side and was yelling across the aisles that they were shutting down the debate and pulling the bill," Crowley told reporters shortly after the incident.
"I said to him then, the staffer is shutting down democracy! And he said, 'That's right,'<!p><#148> Crowley said.
Crowley said it was the aide who was out of line and who in fact apologized for his conduct after the encounter. A Cantor spokesman said later that all sides had spoken and resolved the matter.
Talks were expected to continue in the Senate through Sunday, where several members expressed hope that a breakthrough was not far off -- always darkest before the dawn, and all that.
"There's good discussion going," said Sen. Timothy Kaine, D-Va., generally one of the chamber's sunniest members. "I see us getting there, in fits and starts."
But, he conceded: "I think people are pretty tired and haggard."