It’s crunch time for Republicans – again – on another healthcare bill, and it appears the party is right on the edge of passage in the Senate.

The latest, and likely last, chance the GOP has to repeal and replace Obamacare (for at least a while) is the Graham-Cassidy-Heller-Johnson legislation. The plan would shift federal funding for healthcare to up-front block grants based on a state’s population.

Sen. Bill Cassidy, one of the bill’s authors, has said are 48 to 49 GOP senators on board with the plan. One Republican senator also told Politico the GOP is “one vote away from doing this thing.” Republicans need 50 votes to pass the bill – and their ability to do so without facing a Democratic filibuster expires at the end of the month.

Republicans can only afford two defections for the bill to pass. Here are the Republican senators who could decide the bill’s fate.

Lisa Murkowski, Alaska

Why she could oppose: Murkowski voted against the last Senate Obamacare repeal plan. Her concerns included the loss of money for her state’s Medicaid program and the proposed defunding of Planned Parenthood. Both of those potential sticking points remain in the new proposal. In fact, one analysis from the progressive Center on Budget and Policy Priorities projected Alaska would lose $255 million through 2026.

Rand Paul, Kentucky

Why he could oppose: Well, he already said he plans to. Paul tweeted that the plan was “Obamacare-lite” and would do little to undo the regulatory structure of the current system. He also said the bill leaves in place the “entitlements” in Obamacare. The public repudiation seems to make him a safe “no” for now.

Susan Collins, Maine

Why she could oppose: Another senator that opposed the earlier Obamacare repeal plans, Collins could also be worried about the loss of funding her state could see. According to the CBPP, Maine would stand to lose $115 million under the plan. Collins has also opposed previous plans to defund Planned Parenthood.

John McCain, Arizona

Why he could oppose: McCain also voted against the previous Senate healthcare plan and was seen as the deciding vote in a dramatic late-night moment. McCain criticized the lack of committee hearings and the procedure on the new legislation when talking to reporters Monday. (There have been two hearings scheduled for the bill.)

The wild cards

Several other states could end up losing money under the legislation. Senators such as West Virginia’s Shelley Moore Capito, who was on the fence about the previous healthcare legislation before ultimately voting for it, have expressed concerns about provisions such as Medicaid cuts that are part of the GCHJ.

SEE ALSO: Republicans’ last-chance Obamacare repeal has a giant money problem»