And President Donald Trump, whose White House was optimistic the House could pass a bill Wednesday, once again muddied the waters by suggesting the measure may still be changed.
Vice President Mike Pence, who has been working with congressional leaders from the start on the health care effort, is heading up to Capitol Hill Monday afternoon as well.
The Republican Party can only afford to lose 22 votes assuming all of the Republicans are able to attend the vote and no Democrats cross over. As they count votes, GOP Rep. Jason Chaffetz, who was expected to be out for three to four weeks after surgery, is returning Monday from Colorado and will back the bill, his office said.
Most notably Monday, Rep. Billy Long, a Republican from Missouri who serves on the Energy and Commerce Committee, announced he was opposed to the legislation. Reps. Brian Fitzpatrick of Pennsylvania, Daniel Webster of Florida and Chris Smith of New Jersey will also vote against the current bill, making their decisions public in succession Monday afternoon.
As hard as it is, Republican congressional leaders know they can't simply abandon their effort now.
"I hope we keep going. I don't think we can stop," said Rep. Brett Guthrie, a Republican who serves on the House's Energy and Commerce Committee told CNN last week.
White House chief economic adviser Gary Cohn sounded optimistic Monday morning when asked if he thought Republicans' plans for health care had enough votes.
"I think we do," Cohn told CBS. "This is going be a great week. We're going to get health care down to the floor of the House. We're convinced we've got the votes and we're going to keep moving on with our agenda."
The fight over how pre-existing conditions are covered is at the center of the fight.
Trump said Sunday the White House is pushing forward, and that the GOP plan "guarantees" coverage for Americans with pre-existing conditions.
"Pre-existing conditions are in the bill. And I mandate it. I said, 'Has to be,'" Trump said on CBS's "Face the Nation" Sunday.
Unlike the mandate under Obamacare, however, under the GOP bill insurers could charge them higher rates than others in the plan if they allow their coverage to lapse.
Republicans might seem stuck in a never ending cycle of trying to please the moderate and conservative wings of their party but pressure from the White House to deliver a legislative win for Trump is real. Also real: the repeated pledges to their constituents over the past seven years to repeal and replace Obamacare if given the chance.
MacArthur amendment not enough?
Last week, Republicans seemed to reach a major breakthrough on health care.
A new amendment sponsored by moderate leader Rep. Tom MacArthur of New Jersey gave states the ability to opt out of more Obamacare regulations. The amendment was also enough to finally bring the conservative House Freedom Caucus on board.
But the amendment, which experts noted could drive up the cost of insurance for older Americans and those with pre-existing conditions, spooked moderates and left some -- who had been supportive of the legislation before -- scrambling to publicly voice their discontentment. All of a sudden, it was moderates in the hot seat.
It seemed that even though leadership may have gained upwards of 30 new votes from the Freedom Caucus, they were suffering significant enough losses from the other side of the party that they still couldn't bring a bill up to the floor for a vote in order to mark Trump's first 100 days in office.
This week, leadership's focus remains trying to help those moderates get comfortable with the new MacArthur amendment. Over the weekend, House leaders, as well as Pence and Health and Human Services Secretary Tom Price, spoke with members hoping to flip enough votes to move the bill forward. Leadership aides emphasize that there isn't much room to change the proposal at this point, but many deputy whips are trying to get members to keep the process in perspective.
"You remind them there is a United States Senate, and it will change things. What we send over there isn't going over there on stone tablets," said Rep. Tom Cole, R-Oklahoma.
"Going back to the drawing board would be death to repeal and replace," one aide said.
After last week, though, many moderates are frustrated with the process. Some say they see their party making the same kind of mistakes Republicans criticized Democrats for making back in 2010.
"We didn't learn anything from their mistakes," said Rep. Mark Amodei, a moderate Republican from Nevada told CNN. "We learned nothing from their mistakes."
As to promises the bill will be changed once it's in the Senate?
"Seriously, you want me to go back and tell the people in my fourth of Nevada 'the Senate will make it