Washington (CNN) Top White House officials descended on Capitol Hill Thursday night to personally deliver President Donald Trump's ultimatum to House Republicans: Negotiations on their health care bill are over, and the House will vote Friday.

Then, there was this: If the bill doesn't pass Friday, Trump is ready to move on and Republicans will be "stuck with Obamacare."

That message, conveyed by Office of Management and Budget Director Mick Mulvaney to tired lawmakers over Chick-fil-A and Corner Bakery snacks, finally put an end to the looming question of whether the GOP health care legislation would end up on the House floor. It also dared Republican critics and skeptics of the bill like the conservative House Freedom Caucus to own the political consequences of reneging on the party's years-long pledge to gut President Barack Obama's landmark health care law.

The outcome of Friday's vote is unclear. If the bulk of the Freedom Caucus remains opposed to the bill, leadership does not believe it has the votes to clear the bill in the House.

According to CNN's ongoing whip count, 27 House Republicans have said they will vote against the bill and four more have indicated they are likely to oppose it. Republicans can't lose more than 21 members of their caucus and still pass the bill, since no Democrats are expected to support it.

The dramatic scene on Capitol Hill followed 24 hours of tense negotiations and hushed meetings on both ends of Pennsylvania Ave. By Thursday afternoon, GOP leaders had postponed the vote scheduled for that day.

The decision to end negotiations came from the White House, a person with direct knowledge said. Leadership and top White House aides spent the late afternoon "trying to grind them down," the source said, referring to the Freedom Caucus. But there was no clear progress, so in private conversations, even as meetings were ongoing with the Freedom Caucus, Trump made the decision to go ahead with the vote.

"There's nothing more we want to -- or really can -- give them," the source said

Trump and House Speaker Paul Ryan spoke by phone for nearly 45 minutes late Thursday, multiple sources told CNN. A source familiar with the discussions said was an "entirely positive call."

But the struggle to repeal Obamacare has highlighted both Trump's and Ryan's struggles to reconcile their own party's deep and glaring internal divisions.

Both men have been furiously lobbying lawmakers and especially the Freedom Caucus to get behind the legislation, as the group has tried to push the bill to the right but whose proposals have alienated moderate Republicans.

Meanwhile, the Congressional Budget Office came out with more bad news on Thursday. Changes Republicans made earlier this week to the bill will actually only decrease federal deficits by $150 billion over 10 years, while the original measure would have lowered deficits by $337 billion.

The measure still would leave 24 million fewer people insured by 2026 than under Obamacare, CBO said.

The challenge for leaders as they've counted their votes has been daunting: Give conservatives too much of what they want and risk losing the moderates, but keep the moderates on board and conservatives could walk.

On Wednesday and Thursday, non-Freedom Caucus Republicans began to turn their backs on the bill, saying it was not a plan they could back on behalf of their constituents.

The moderate Tuesday Group trekked to the White House Thursday afternoon after intense deliberations of their own and a meeting with Ryan. The group had seven boxes of pizza as well as Doritos and Baked Lays delivered to a room in the Capitol earlier in the day.

Even after Trump delivered his ultimatum Thursday night, some of the moderate Republicans previously opposed to the bill -- such as New Jersey Rep. Leonard Lance -- said they would still vote "no."

In trying to win votes for the health care bill, Trump has also experienced firsthand the reality of what it can be like to work with the Freedom Caucus, a top GOP source said -- that they can be deeply frustrating because they don't really want to get to yes and keep changing their demands.

The drawn-out exercise has also created hard feelings within the House GOP conference.

Alabama GOP Rep. Bradley Byrne, emerging from a meeting with top House leaders on Thursday, blasted the House GOP leadership's move to continue talks with the hard right in the Freedom Caucus while leaving the bulk of other members in the dark.

"I think the window for making decisions is rapidly closing. We need a vote or go home," said Byrne, a member of a large group of fiscal conservatives, the Republican Study Committee.

Moderates are unhappy

A key element of the negotiations between the Freedom Caucus and the White House revolved around the so-called "essential health benefits." Obamacare mandated that certain insurers to cover 10 services, including maternity, prescription drugs, substance abuse and mental health.

It has made coverage more comprehensive and prevented insurers from selling skimpy plans that were cheap, but didn't offer many benefits -- often leaving consumers with big bills if they needed care.

On the flip side, the measure has also driven up premiums and restricted consumers' choice to buy more limited coverage. Republicans have long wanted to get rid of the essential health benefits provision, which is key to their pledge to reduce premiums and offer choice to consumers.

Removing the provision could also greatly weaken the law's protection of those with pre-existing conditions. Without the requirement to cover comprehensive policies, insurers could opt exclude some of the priciest services that sick Americans.

The final bill that Republicans will vote for on Friday would repeal the essential health benefits provision.

That decision has frustrated plenty of Republican lawmakers.

"A lot of people don't realize what the implications of that are," one lawmaker said. "So we're gonna railroad this thing through and there's going to be even more people pissed off -- our constituents, stakeholders."

What's in the bill

The GOP health care bill, introduced earlier this month, would roll back many of the Obamacare taxes and eradicate the individual mandate. Instead of the subsidies available under Obamacare, officially known as the Affordable Care Act, the GOP plan provides Americans with refundable tax credits to purchase health insurance.

The bill also significantly restructures Medicaid and allows states to require able-bodied adults to work if they want to be eligible for the program. After 2020, states will no longer be able to expand Medicaid like they could under Obamacare and states that haven't expanded the program at all are barred from doing so.

However, the GOP bill still includes some of the most popular pieces of Obamacare, including letting children stay on their parents' insurance plans until the age of 26 and including protections for people with pre-existing conditions, though insurers would be allowed to charge higher premiums to individuals whose coverage has lapsed.

This story will continue to be updated as developments warrant.