Republicans are moving quickly on a last-minute repeal of the Affordable Care Act that could have a bigger impact on health insurance markets than any previous Republican plan this year.

It’s still unclear whether the legislation unveiled by Sens. Lindsey Graham, R-S.C., and Bill Cassidy, R-La., last week has the votes to pass the Senate and get approval by the House of Representatives.

But there’s urgency to act before a Sept. 30 deadline that would allow the Senate to make changes to the ACA with only 50 votes. After that, 60 votes would be needed, a tough challenge given the slim majority the GOP holds in the Senate.

The Graham-Cassidy legislation has been months in the making but only in the last week has gained traction, garnering support from the Trump administration and Senate GOP leadership.

Read More About Healthcare Reform

The legislation calls for eliminating federal funding for the ACA and turning a set amount of the money over to states to provide insurance coverage for residents. It also allows states to apply for waivers on key provisions of the ACA.

Republican supporters say the bill will give states more control over their insurance markets and the ability to offer a variety of policies with different costs and benefits.

But some health policy analysts, consumer advocates, and a bipartisan group of governors say the legislation could leave millions of people without affordable insurance.

“This is more draconian in many ways than anything we've seen before,” says Linda Blumberg, senior fellow in the Health Policy Center at the Urban Institute. Because federal funding for the ACA will eventually be cut off and states left with more limited funds to provide insurance, “the number of people who will be uninsured will be much larger than what has been previously proposed.”

“The Graham-Cassidy proposal shifts billions of dollars of healthcare costs onto states and consumers,” says Betsy Imholz, special projects director for Consumers Union, the policy and mobilization arm of Consumer Reports. “Worse yet, it’s being rushed through the Senate without enough time for an independent analysis of exactly how it would impact people’s access to coverage and costs. We’re calling on lawmakers to soundly reject this bill.” 

Meanwhile, a bipartisan effort in the Senate to stabilize ACA insurance markets collapsed late Tuesday. In a statement, Sen. Lamar Alexander, R-Tenn., head of the Senate Health, Education, Labor and Pensions Committee, said: “During the last month, we have worked hard and in good faith, but have not found the necessary consensus among Republicans and Democrats to put a bill in the Senate leaders’ hands that could be enacted.”

How the ACA Could Change

Here is what the Graham-Cassidy legislation would do:

Phase out ACA funding. The biggest change from earlier GOP proposals is to replace federal funding and give states block grants that they could use to fund health insurance and healthcare for residents. The Graham-Cassidy bill would eliminate federal funding for the 31 states that expanded Medicaid coverage to cover a larger group of low-income people.

It would also end ACA subsidies that lower premiums, deductibles and co-pays by 2020. States would instead receive a lump sum of money annually. States would have a lot of leeway on how to spend it. But that funding would end entirely by 2027.

Allow insurers to charge sick people more. Although it would still require insurers to provide coverage to everyone, it would allow states to apply for waivers to enable carriers to charge enrollees more based on their medical history. Younger, healthier people could see their premiums go down, but sicker people would face significantly higher premiums.

The liberal Center for American Progress (CAP) did an analysis of premiums if insurers can price policies taking health status into account. Using data from the Centers for Medicare and Medicaid Services, CAP estimates that a 40-year-old person in average health would pay an average $6,050 in annual premiums. Someone with asthma would pay an additional $4,340 per year on top of that, a pregnant woman would pay $17,320 more annually than a healthy person, and a person suffering from lung cancer would pay an additional $72,000 premium surcharge.

States could also waive an ACA requirement that insurers cover 10 essential health benefits, including hospital stays and maternity care. Insurers could offer lower-cost policies for less comprehensive coverage. But if you need care that’s not covered, you’ll have to pay for it out of pocket.

Slash funding for Medicaid. Like earlier bills, Medicaid would be cut deeply, affecting the largest number of people who have insurance under the current ACA law. In addition to Medicaid expansion funding being eliminated by 2026, funding for the existing Medicaid program, which provides health insurance to low-income Americans, the elderly and children, would be capped on a per-person basis. 

Deadlines Looming

The Congressional Budget Office, which must provide an analysis of the impact of the legislation on federal spending before it can be voted on, says it will release a preliminary report on the legislation early next week. In contrast to earlier analyses, the CBO said it wouldn’t be able to provide estimates on how the legislation would affect the number of people insured or premiums. A Senate vote could come after the CBO report next week.

Meanwhile, another key deadline is approaching: By Sept. 27, insurers must sign final contracts with the federal government for the plans they offer. Though every ACA insurance market currently has at least one insurance company offering plans, insurers can pull out of ACA markets up until contracts are signed. Even in counties where insurers remain, people who don’t get government subsidies face steep premium increases in 2018. 

All this is happening as consumers get ready to make decisions about whether to renew or sign up for individual health insurance plans when the ACA enrollment period begins Nov. 1. Some of the changes proposed by the Graham-Cassidy legislation will kick in immediately, such as repealing the individual mandate that requires people to buy health insurance or pay a penalty. That could have an immediate impact on the insurance markets.

Without a requirement to buy insurance, the higher premiums expected in many ACA markets for 2018 could discourage healthier people from signing up. That would further boost insurer costs because they would have a larger pool of costly people to cover and would boost rates even more in the short term.