Story highlights Republicans are trying to replace Obamacare before a September 30 deadline

The most recent bill has two public no votes and faces an uphill climb

(CNN) Despite Arizona Sen. John McCain's decision to oppose the latest Republican health care plan to repeal and replace the Affordable Care Act, the effort is still ongoing, GOP aides say -- at least for the moment.

Multiple aides involved in the process say the focus on winning Alaska Sen. 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.

"We're still working," said one GOP source involved in the process. For now, the source says, there are only two public "no" votes -- McCain and Kentucky Sen. Rand Paul.

Even though Maine Sen. Susan Collins has said publicly she's "leaning against" the bill and has long been expected by Senate leaders to end up opposed, with only two firm "no" votes, the effort still has life, as tenuous as it may be.

"Whatever sports metaphor you want to use about how it would take a miracle, it's that," another source acknowledged, noting that even a "Hail Mary" might be too generous to describe the odds at the moment.

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