A group of Republicans just launched a desperate Hail Mary to repeal Obamacare

A group of Senate Republicans on Wednesday rolled out a last-ditch effort to repeal and replace the Affordable Care Act, but it faces an almost-certain legislative roadblock.

The bill was written by Sens. Lindsey Graham, Bill Cassidy, Dean Heller, and Ron Johnson and would primarily allocate federal funding for healthcare in block grants to states, a change from the current system that allocates money based on a percentage of what states spend.

Graham, in a statement announcing the release of the bill named after the senators, touted the idea as a way to give flexibility on healthcare spending to states.

"Our bill takes money and power out of Washington and gives it back to patients and states," Graham said. "It takes us off the path to single payer healthcare - which would be a disaster - and puts us on a path toward local control."

The bill has drawn the support of some prominent Republicans, including the pivotal vote that killed the first GOP Obamacare repeal push: Sen. John McCain. But it does not appear to have the necessary support to pass the Senate.

Sen. Ted Cruz said the bill has the support of around 46 members of the GOP conference. Senate Majority Leader Mitch McConnell reportedly said that the bill would get a vote if the senators can convince 50 GOP members to support it. Typically, leadership would try and find votes for a bill it supported.

The budget reconciliation process by which Republicans would have to move the bill also presents the biggest challenge, as it stamps a serious time crunch on their effort. The reconciliation rules that allow the bill to pass the Senate with a simple majority, and avoid a Democratic filibuster, are set to expire at the end of the month.

Sen. John Thune, the third-ranking Republican member of the Senate, told reporters that the bill would need a "double-double bank shot" in order to pass.

Another sticking point is whether key provisions of the proposal would qualify for budget reconciliation under what is known as the Byrd rule. Any part of the bill that does not affect the budget would be stripped out.

Here's a quick rundown of what the proposal would do:

• Shift Medicaid funding and insurance subsidies to a block-grant system: Instead of determining the federal government's share of funding for Obamacare's Medicaid expansion and individual insurance subsidies through a formula, states would receive large chunks of money up front based on a per capita formula that measures how many people of certain health statuses were living in the state. How much money each state would get would be based on a complex formula that could cause a significant shift in federal funding among states. Just under $1.2 trillion would be allocated for this purpose from 2020 through 2026.
• Pay cost-sharing subsidies through 2019: Such a move would help the Obamacare exchanges stay stable in the short-term, something Democrats have urged. When the block grants kick in, however, these payments would end.
• Maintain many Obamacare taxes: To avoid adding too much to the federal deficit, and disqualify for the reconciliation process, the bill would preserve many major Obamacare taxes - like the tax on net investment income.
• Eliminate the individual and employer mandate: People who do not sign up for insurance would not face a tax under the plan, and companies would not be compelled to offer coverage. States could pass their own mandates, however.
• Include a state stability fund: The bill would allocate $10 billion in 2019 and $15 billion in 2020 for states to help bring down premiums and set up programs to get people coverage.
• Cut off money from abortion providers: None of the money allocated from the bill could go toward healthcare providers that offer abortion services.