Republicans struggle to move forward on Senate health care bill

Collins was joined by several other Republicans in publicly saying that without changes, they are not ready to begin debate this week:

Also ready to vote against the "motion to proceed" to the health care bill - Sen. Rand Paul (R-KY), and Sen. Dean Heller (R-NV).

Democrats meanwhile used speeches on the Senate floor - and social media outside on the steps of the Capitol - to make their argument that the GOP bill should be shelved immediately.

The original plan had been for the Senate to vote on Tuesday to begin debate on the GOP health care bill, with a final vote expected on Thursday or Friday - but that timeline seemed to be on hold for the time being.

Earlier on Monday, the Congressional Budget Office found that the plan would mean 22 million fewer people would have health insurance by 2026, not much different than the estimates for a similar bill that was approved by the House in early May.

The CBO report found that of the 22 million - 15 million would lose insurance coverage from changes to the Medicaid program, while another 7 million people would lose coverage because of changes in the nongroup and individual insurance marketplaces.

The CBO review had good news on the money front for the GOP, as the plan would save an estimated $321 billion over ten years on the federal deficit, spending $1.022 trillion less than current law, while reducing federal tax revenues by $701 billion from 2017-2026.

The White House derided the CBO report, arguing their estimates have never been close; meanwhile, the President was doing what he could do from the sidelines to try to sway Republicans to his side.

"He made several calls to multiple Senators to hear their concerns and get their ideas, and understand where they're at and what needs to get done," said White House Press Secretary Sean Spicer.

But with Republicans only able to lose two votes, GOP leaders were struggling to keep the GOP health bill on track in the Senate.