Washington (CNN) House GOP leaders, despite a furious push Thursday, were unable to wrangle the votes necessary to move forward on their latest effort to repeal and replace the Affordable Care Act.

The development short-circuits, yet again, the House effort to repeal the cornerstone domestic achievement of President Barack Obama.

It guarantees President Donald Trump will be without a cornerstone legislative achievement on his 100th day in office -- a symbolic moment that the White House has focused on intently in recent days as negotiations on a revised health care proposal accelerated.

"There will be no vote tomorrow," House Majority Leader Kevin McCarthy told reporters as he departed a nearly two-hour closed-door meeting of House leaders as they sought to plot a path forward on the bill. Asked if there was any chance there would be a vote at any point this weekend, McCarthy also said no.

"We've been making great progress," he said. "So when we have the votes we'll vote on it."

The failure to collect the 216 votes needed to pass the bill marks yet another setback on the House -- and White House -- efforts to see the central GOP campaign promise of the last seven years even reach the House floor.

Despite robust conservative support for the proposal, Republican leaders found themselves bleeding support from the conference's more centrist members, many of whom voiced concern over whether it would undercut the existing ban on pre-existing conditions.

CNN count of where members stood had 16 solid "no" votes on the bill and another 11 members undecided.

Still, a GOP leadership aide said the proposal, which brought Republicans closer to the requisite number of votes needed to pass a bill than any of the previous iterations, was "100 percent" still alive.

"We're close, and moving in the right direction, but not close enough to risk it," the aide told CNN. That indicates that GOP leaders still see a window to move the bill, possibly as soon as next week. But there is unquestionably work to do.

"We're still educating members," McCarthy said.

Focus on GOP moderates

Before the recess, all eyes were on the conservative House Freedom Caucus, whose coalition of more than 30 members had stood united against House leadership's health care bill. Now, however, with a new amendment that gives states broader ability to opt out of Obamacare regulations and roll back protections for individuals with pre-existing conditions, moderates are the ones taking the heat.

Rep. Charlie Dent, a moderate Republican from Pennsylvania, called it "an exercise in blame shifting."

The amendment was negotiated between Tuesday Group leader Rep. Tom MacArthur, a moderate Republican from New Jersey, and House Freedom Caucus Chairman Mark Meadows, with consultation from the White House and House leadership. It has caused a lot of heartburn among moderates, with many arguing that they had explicitly asked their leadership not to negotiate with the Freedom Caucus.

MacArthur defended his amendment to reporters Wednesday.

"The latest proposal I made was just trying to bridge this divide between people that are holding two important views: people that are saying 'we're not going to fix health care unless we bring the cost down, which means we have to give the states some flexibility,' and people that are saying 'we can't pull the rug out from under people that are vulnerable," MacArthur said.

"And I agree with both of those. They are both right positions, and my amendment was just meant to bridge the divide between those two."

What the GOP health care bill does

The MacArthur amendment would allow states to seek waivers to weaken several key Obamacare insurance reforms that protect those with pre-existing conditions, including the benefits insurers must cover in their policies and the ban on allowing carriers to charge more based on a person's health background.

However, Americans who were continuously insured could not be charged higher premiums because of pre-existing conditions. Also, states that waived the ban would have to put in place protections to minimize cost increases for those with pre-existing conditions, such as high risk pools.

The amendment would also allow insurers to hike premiums on older consumers in states that obtain waivers. The original House GOP bill allowed insurers to charge older consumers five times more than younger ones, but states that request waivers could permit insurers to increase those premiums even more.

The waivers would be pretty easy to get, as long as the state explains how it would reduce average premiums and increase enrollment. They'd be automatically approved within 60 days, unless the Health Secretary objects. And they'd last for 10 years.

The amendment initially called for exempting members of Congress from these waivers, however Republicans quickly filed another bill striking that provision.

While MacArthur stressed that states would not be allowed to waive the Obamacare rule that requires insurers to cover those with pre-existing conditions, health policy experts say the amendment would greatly affect those who are sick or have had medical issues in the past. It would allow insurers to charge them more for coverage, and also it would let insurers once again offer skimpy policies. That would make it harder for the sick to find comprehensive policies that cover their treatments.

Obamacare's protections for those with pre-existing conditions are among the law's most popular provisions.

Likely no shutdown

On a positive note for Republican leaders, the failure to move health care this week does appear to clear the path for something else: keeping the government open through May 5.

House Democrats threatened to oppose a short-term government funding bill headed to the House floor tomorrow if Republicans insisted on also voting on their health care bill. That proposal, which would extend Friday's government funding deadline for a week, is designed to give House and Senate negotiators more time to hammer out the final details of a longer term spending package to fund the government through September.

The battle over a government shutdown appeared to be mostly over late Thursday, with the push for border wall funding sidelined and Democrats saying Trump's administration will continue paying for subsidies for low-income Americans as part of Obamacare.

The House is expected to vote Friday to keep the government open through May 5 and give lawmakers more time to negotiate a longer-term funding package.

The border wall and the health care spending had been two sticking points for congressional and White House negotiators during the past several weeks of discussions to avert a shutdown.

White House officials told Democrats on the Hill Wednesday that the Trump administration will continue making the cost-sharing payments created under Obamacare, multiple sources tell CNN.

As part of the Affordable Care Act, the federal government pays health insurers to reduce the out-of-pocket costs for low-income people trying to pay for health care. These are referred to cost-sharing reduction (CSR) payments. The payments are a major way Democrats ensured low-income people would be covered under the Affordable Care Act, but with a new Republican administration, their future is uncertain.