The legislation would do away with Obamacare's individual mandate requiring most Americans to buy health insurance or pay a fine.
The latest Republican attempt to repeal and replace Obamacare appeared headed for defeat after Senator Susan Collins said she doesn't see herself backing the plan and Texas Senator Ted Cruz said he's now "not a yes".
Republicans, who have just a 52-48 majority, are using a special budgetary procedure that allows them to pass legislation with a simple majority - and the vote of the vice president in the event of a tie - rather than the usual 60 votes. GOP leaders are also expected to unveil their most detailed blueprint yet of the tax reform plan they hope to pass by the end of the year.
The GOP bill would abolish much of President Barack Obama's 2010 health care overhaul and shift money and decision-making to the states.
In a string of comments, Trump has also attacked Paul and McCain for their opposition to the repeal. The bill's chief authors, Sens.
Here's what Trump's tweeted about Paul: "I think he may find a way to get there for the good of the Party!"
Trump appealed to Sen. John McCain announced he wouldn't back the proposal. Lisa Murkowski's vote has continued into the weekend, with changes seen to benefit her state related to the state's funding formula in the bill and the timeline for implementation.
Given the opposition from Paul and McCain, a decisive "no" from Collins would be enough to kill the measure, which may not be put up for a vote if its prospects seem doomed.
Trump also is lashing out at Alaska Sen. She expects CBO to reinforce other private reports like one from the Brookings Insititution that shows 21 million fewer people would be insured by 2026 if the law were enacted, as opposed to projections under current law.More news: Things to Watch on Catalonia's Referendum
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She added, "The problem is, CBO may have a very hard time analyzing the bill because it still seems to be a moving target, even over the weekend". Susan Collins all but closed the door on supporting the last-ditch effort to scrap the Obama health care law and Sen.
At a rally in Alabama Friday night, the president said he was stunned by the Arizona senator's vote against the previous repeal bill, saying McCain's opposition was "totally unexpected" and "terrible". For now, the source says, there are only two public "no" votes - McCain and Kentucky Sen.
Trump says the bill would be "great for Arizona" and he says McCain "let his best friend L.G. down!"
"I can not in good conscience vote for the Graham-Cassidy proposal", McCain said in a public statement.
"John McCain never had any intention of voting for this Bill, which his Governor loves". Lindsey Graham, R-S.C., one of the measure's sponsors, said Republicans would press ahead with a vote this week.
To make a September 30 deadline, Republican senators meant to bring the bill offered by Graham and Sen.
Graham said he's "completely convinced" that giving money back to the states is the correct way to address health care and vowed to "press on".
Trump appears to be on an offensive aimed at getting Paul on board with the bill, whom he has generally had a cordial rapport with, while Senate leadership is focusing on winning over Trump critics Collins and Murkowski.