Once thought to be the policy equivalent of a Hail Mary pass, the plan to replace the Affordable Care Act (ACA) known as the Graham-Cassidy bill appears to have gained momentum—and with it, extra attention from healthcare industry groups like the American Medical Association (AMA) that have opposed Republicans’ so-far unsuccessful efforts to repeal the law.

The legislation, named after the two Republicans most instrumental in crafting it, Sens. Lindsey Graham of South Carolina and Bill Cassidy, MD, of Louisiana, is centered around block granting much of the ACA’s funding, with the argument it will create additional flexibility for states. Like past ACA repeal bills introduced this year, it would also allow states to more easily waive ACA requirements on essential health benefits and not varying premiums based on health status. To the AMA, the result would be insufficient Medicaid funding, unaffordable premiums for patients with pre-existing conditions and limiting access to certain services.

“Similar to proposals that were considered in the Senate in July, we believe the Graham-Cassidy Amendment would result in millions of Americans losing their health insurance coverage, destabilize health insurance markets, and decrease access to affordable coverage and care,” AMA CEO James Madara, MD, said in a letter to Senate leaders.

As with past repeal bills, no major healthcare organization has come out in favor of it, while the American College of Physicians, America’s Essential Hospitals and 16 patient and provider groups led by the American Heart Association are also against the bill, arguing much of it “just repackages the problematic provisions” of the Senate Republicans' earlier, failed effort at repeal-and-replace. The same groups urged legislators to instead focus on the short-term stabilization efforts which had been discussed by both parties in the Senate health committee. Its Republican chair, Sen. Lamar Alexander of Tennessee, declared that effort dead on Sept. 19 while his Democratic partner in those talks, Sen. Patty Murray of Washington, said it stalled because Republicans are "trying to jam through a partisan Trumpcare bill."

The party faces a Sept. 30 deadline to pass a bill with only 50 votes in the Senate under the budget reconciliation process. The timeline is so compact that the Congressional Budget Office said it won't be able to fully measure the bill's impact on insurance coverage and

“The odds are improving,” Sen. John Thune, R-South Dakota told POLITICO. “I told Bill Cassidy he’s the grave robber. This thing was six feet under. And I think he’s revived it to the point that there’s a lot of positive buzz and forward momentum.”

One Republican, Sen. Rand Paul of Kentucky, has already said he’ll vote against the bill, arguing it leaves too much of the ACA—such as its health insurance tax—in place. Sen. John McCain, R-Arizona, who was the deciding vote against the Senate’s repeal effort in July, said he’s not supportive of it yet, saying “we need to go to regular order.” The other July “no” votes among Republicans—Sens. Lisa Murkowski of Alaska and Susan Collins of Maine—are officially undecided, though Collins did say the legislation has "additional flaws" compared to the previous bills she voted against and is co-sponsoring an ACA resinsurance proposal with Democratic Sen. Bill Nelson on Florida.

The bill's impact won't be fully measured by the Congressional Budget Office before the Sept. 30 deadline. The complex formula the bill proposes to use would steer money away from the states which chose to expand Medicaid towards those which didn’t. This would largely harm states controlled by Democrats and benefit states run by Republicans.

Those state-level concerns led to 10 governors—including four Republicans and an Independent—to ask the Senate to ditch the bill. Rebekah Gee, MD, the secretary of health in Louisiana, Cassidy’s home state, bashed the bill for punishing states which chose to expand Medicaid under the ACA.

“The combined effects of the per capita caps and eliminating expansion would result in a projected loss of $3.2 billion in federal funding through 2026—making Louisiana the eighth biggest loser of those states affected by the legislation and by far the poorest and sickest states affected by these cuts,” Gee wrote.

In the absence of a full CBO analysis on how the legislation could affect premiums and insurance coverage, liberal-leaning think tanks have offered their own reports. The Center for Budget and Policy Priorities said along with the end of the Medicaid block grant in 2027 resulting in a more than $250 billion cut compared to current law, the bill would destabilize the individual insurance market.

The Center for American Progress (CAP) estimated what insurers would charge to customers with pre-existing conditions. The highest surcharge would be an estimated $142,650 hike for patients with metastatic cancer.

“Graham-Cassidy would have the same nightmarish impact on individuals with pre-existing conditions that the previous House and Senate repeal bills would have had,” said CAP health economist Emily Gee.

Several hurdles for the bill remain to be cleared before the Sept. 30 deadline for the bill to pass under budget reconciliation rules. The CBO has promised to provide a “preliminary assessment” of the legislation on the week of Sept. 25. Two Senate hearings on portions of the bill have been also been scheduled: one taking place in the Senate Homeland Security and Governmental Affairs Committee, which has no jurisdiction on healthcare policy, and a Sept. 25 Senate Finance Committee hearing, the scheduling of which was criticized by its ranking Democrat, Sen. Ron Wyden of Oregon, as an “abomination,” according to The Hill.