CNN  — 

The debt ceiling deal proposed by Senate Minority Leader Mitch McConnell put his GOP conference in a bind, with some Republicans accusing the formidable Senate tactician of folding in his standoff with Democrats and others refusing to go along with his strategy.

The Senate voted 50-48 Thursday evening to extend the nation’s debt limit through early December, but despite three meetings in the span of 48 hours, Republicans had remained at loggerheads ahead of the vote.

During a private 90-minute meeting, Sen. Ted Cruz of Texas sharply disagreed with McConnell’s strategy – and insisted he would force the 60-vote threshold on the GOP leader’s plan to avoid a debt default until early December. That meant 10 Republicans would be forced to break a GOP-led filibuster in order to allow the debt ceiling increase to move ahead. Eleven Republicans eventually broke ranks to clear that hurdle.

A number of GOP senators, such as fellow conservative Sen. Ron Johnson of Wisconsin, made the case that the McConnell deal – while far from ideal – should be allowed to pass with just 51 votes, allowing Democrats to vote for it and Republicans to vote against it. But Cruz – along with his two allies, Sens. Mike Lee of Utah and Rand Paul of Kentucky, who were not at the meeting – showed no signs of relenting.

The divisions over strategy and policy undercut the GOP leader’s long-prized effort to maintain unity amid high-profile fights with Democrats. And it comes as Republicans are openly questioning his move, which he has privately defended as necessary to ensure that Democrats don’t take steps to weaken the Senate’s filibuster rules, which give power to the minority party to scuttle the majority’s agenda.

Sen. John Kennedy of Louisiana said he was “very disappointed” by McConnell’s decision to allow Democrats to pursue a short-term debt ceiling hike under normal procedures. Cruz called the strategy a “serious mistake” and said he thinks “Democratic threats to destroy the filibuster caused him to give in.” And Sen. Lindsey Graham of South Carolina complained that “we had a plan and he threw it over.”

“Why the hell would I make it easier for them to raise the debt ceiling through regular order?” Graham added in a statement.

McConnell has defended his approach both in public settings and behind closed doors, signaling to members that the future of the Senate rules may have been at stake.

One Republican senator defended McConnell, saying that “you would have to ask McConnell more about the conversations he had with (moderate Democratic Sens.) Joe Manchin and Kyrsten Sinema. I just believe in his estimation, it is about saving the institution of the Senate.”

McConnell had also argued that helping Democrats punt the debt ceiling crisis now undermines Democrats’ argument that they don’t have enough time to use the complex budgetary process known as reconciliation to lift the nation’s borrowing limit. And McConnell pointed out that, as part of the deal, Democrats have to name a fixed-dollar amount to which to raise the debt ceiling – and they will have to own that number.

But not everyone in his conference was in agreement. And the palpable angst among Republicans threw into question whether a debt-ceiling increase could quickly pass the chamber. At issue was rounding up 10 Republicans to allow the debt limit vote to proceed, though Democrats still had to raise the ceiling on their own. GOP leaders had wanted their members to allow a quick up-or-down vote, but some Republicans had signaled they would object in order to force the 60-vote threshold.

Emerging from the closed-door, 90-minute meeting Thursday evening, GOP senators had said it was unclear if there would be 10 senators to break a filibuster on the short-term debt ceiling hike.

“There are disagreements within the conference, which is not surprising,” Cruz said leaving the meeting. “Two days ago Republicans were unified. We were all on the same page. … Schumer was on the verge of surrendering. And, unfortunately, the deal that was put on the table was a lifeline for Schumer, and I disagree with that decision.”

GOP leaders continued to insist they would find a way forward.

“In the end we’ll be there, but it’s going to be a painful birthing process,” Sen. John Thune of South Dakota, the Senate GOP whip, said ahead of the vote.

Inside McConnell’s shift

McConnell for months had been warning Democrats that they will need to go it alone on a debt ceiling hike. That’s why it caught some GOP members by surprise on Wednesday when the Kentucky Republican announced that he was going to offer Democrats a short-term off ramp to the fiscal crisis.

One member described it as “whiplash,” while an aide confided that the discussion in the closed-door conference was a bit “rowdy.”

“Some think that by having this delay, it’s a sign of weakness,” said Sen. Mike Braun of Indiana. “I don’t think so.”

One reason for McConnell’s shift in thinking, according to multiple lawmakers: preserving the filibuster. With Republicans insisting that Democrats raise the debt ceiling on their own through reconciliation, and Democrats refusing to go that route, there were serious conversations inside the Democratic caucus this week about creating a carve-out to get around the filibuster in order to deal with the debt ceiling.

McConnell said during a closed-door lunch this week he was concerned about the pressure on Manchin and Sinema to change the Senate rules, according to sources, even as they showed no signs of budging.

“Let’s save the institution of the Senate, and let’s not test Joe Manchin’s resolve,” said Sen. Kevin Cramer of North Dakota, describing the thinking inside the Senate GOP.

McConnell’s reversal has reverberated beyond the Senate Republican conference.

Conservative Rep. Chip Roy of Texas, a former Cruz staffer, blasted McConnell on Twitter and accused Republicans of folding because they didn’t want to miss a fundraiser being hosted by the Senate GOP’s campaign arm next week.

And former President Donald Trump, who has made bashing McConnell a habit, also accused the GOP leader of caving.

“Looks like Mitch McConnell is folding to the Democrats, again,” Trump said in a statement. “He’s got all of the cards with the debt ceiling, it’s time to play the hand. Don’t let them destroy our Country!” In a statement ahead of the procedural vote Thursday, Trump urged GOP senators not to vote “for this terrible deal being pushed by folding Mitch McConnell.”

Other Republicans, however, came to McConnell’s defense, pointing out he was consistent in not wanting to let the nation default on its debts and arguing Democrats will still have to address the debt ceiling – as well as government funding – in December, a messy scenario right before the holidays.

Cramer called the deal floated by McConnell an “elegant solution” and said, “Mitch is nothing if not efficient.” But he acknowledged that some of his Republican colleagues didn’t share that view.

“It’s been a lot more fun to watch Democrat-on-Democrat than it is to participate in Republican-on-Republican,” Cramer said.

This story has been updated with the Senate voting to extend the debt limit.

Jessica Dean and Ted Barrett contributed to this report.