(CNN) In a desperate search for 50 votes, Republican leaders are trying to convince Sen. Rand Paul of Kentucky to support a health care bill he's spent the last week railing against.

There's little evidence it will work.

Both Vice President Mike Pence and President Donald Trump have reached out to the junior senator from Kentucky in the last 24 hours, and Trump tweeted Saturday morning: "I know Rand Paul and I think he may find a way to get there for the good of the Party!"

I know Rand Paul and I think he may find a way to get there for the good of the Party!

Still, there are no signs that Paul is close to reversing his position on Graham-Cassidy, the latest health care bill, which would repeal the individual and employer mandates in Obamacare, get rid of the subsidies and Medicaid expansion and instead give states block grants to set up their own health care programs.

Paul spokesman Sergio Gor told CNN Friday that Paul is "unlikely" to change his mind even if changes were made to the bill, and a leadership aide said they thought Paul was way too far gone to come back around now.

"Not even a consideration right now," the aide said.

Over the last week, Paul has publicly skewered Graham-Cassidy for not repealing enough of the Obamacare taxes and not going far enough to rein in federal spending. In a Tweet Friday, Paul wrote "Calling a bill that KEEPS most of Obamacare "repeal" doesn't make it true. That's what the swamp does. I won't be bribed or bullied."

Still, the White House isn't expected to lay off. The bill's sponsors as well as the President, are determined to find the votes after months of repeal efforts, and time is almost up. The Senate's vehicle to pass a health care bill with just 51 votes expires at the end of this month, and it only takes one more Republican "no" vote to stop the legislation from passing altogether. Republican leaders need 50 votes to repeal Obamacare. Then, the vice president would cast the final 51st vote.

Calling a bill that KEEPS most of Obamacare "repeal" doesn't make it true. That's what the swamp does. I won't be bribed or bullied. — Senator Rand Paul (@RandPaul) September 22, 2017

The prospects for bringing the bill to the floor next week, however, are dimming.

Friday, Arizona Republican John McCain became the latest "no," saying he could not "in good conscience" support the latest effort to repeal Obamacare. He cited concerns with the Republican's partisan process and their lack of hearings, markups and amendments in the Senate.

"I cannot in good conscience vote for the Graham-Cassidy proposal," the Arizona Republican said in a statement. "I believe we could do better working together, Republicans and Democrats, and have not yet really tried. Nor could I support it without knowing how much it will cost, how it will (affect) insurance premiums, and how many people will be helped or hurt by it. Without a full CBO score, which won't be available by the end of the month, we won't have reliable answers to any of those questions."

On Friday, Sen. Susan Collins, a Republican from Maine, also inched closer to closing the door on Graham-Cassidy, saying that she was "leaning against," the bill, according to a report from The Portland Press Herald