For example, Alabama could get an additional $740 million under the increased match, according to an analysis by the Kaiser Family Foundation.
That's on top of the 90% of the costs the federal government already pays for states that expand Medicaid. Congress also authorized last year a 6.2% increase in the Medicaid match rate in response to the pandemic. The additional federal funding, plus the impact of the pandemic on uninsured patients and financially-strapped hospitals and providers in rural areas, has changed the debate, advocates say.
"I think the dynamics are changing. There is a good amount of Republican support with this," said Jane Adams, campaign director for Alabama Arise and Cover Alabama, two advocacy groups working on Medicaid expansion.
She said many haven't gone public with their support yet and are waiting for Republican Gov. Kay Ivey to respond. Ivey's office recently told local media outlets it would "thoroughly review" the provision and the COVID relief bill before weighing in.
In Alabama, the governor doesn't need approval from the state legislature to expand Medicaid — but it helps.
"Republican legislators previously opposed to expansion are now greatly worried about their health systems in rural counties. COVID changed the perception around access to healthcare," Adams said.
Wyoming is experiencing similar dynamics, where a Medicaid expansion bill passed a key Senate committee last week after years of failed attempts, stunning political onlookers.
Republican Gov. Mark Gordon, who has said in the past he opposes Medicaid expansion, recently said he would give it a "fair hearing" if it passed the legislature.
If the state expands Medicaid to people making below $17,770 a year, it would cover about 24,000 people by the end of the second year of the program, according to recent state estimates.
It would also be a boon for rural Wyoming hospitals,which operate on thin margins and have faced recruiting issues.
"This is very much needed for our state and we believe it will support the entire healthcare system — not just rural hospitals — and it would increase our chances of being able to recruit providers to our state," said Jan Cartwright, director of the Wyoming Primary Care Association.
Hospitals have become some of the biggest backers of Medicaid expansion, largely due to the impact of the uninsured rate on bottom lines.
When patients don't have insurance, they often end up in emergency departments for treatment. People who are uninsured are often low-income, and struggle to pay their medical bills.
Studies have shown the levels of uncompensated care decreases for hospitals in states that expanded in Medicaid. In Louisiana, uncompensated care costs dropped 33% for general medical and surgical hospitals in the first three years of expansion, according to a recent Health Affairs study.
Under the new provision passed by Congress, Wyoming would qualify for an additional $70 million over two years if it expanded Medicaid in additional to the federal government picking up 90% of the costs of covering the new population, according to the Kaiser Family Foundation.
That extra funding would cover the state's share of costs for covering the expansion population for several years, Cartwright said.
"That's 10 years of healthcare for people who really need it," Cartwright said.
"This FMAP Change is a big deal for Wyoming," she said, noting which is also facing a budget shortfall of around $1 billion that the funding could help cover.
Kansas and North Carolina also may eye Medicaid expansion, after Democrats were elected to governorships in 2020. But both states are still dealing with Republican majorities in their state legislatures that have been fairly resistant to Medicaid expansion over the years and are ardently opposed to the ACA.
It's not clear if the additional funding is enough to move the opposition.
"Many (legislators) have been concerned about program costs and this addresses it, but will it be enough to address the politics? That is the barrier," said Cindy Samuelson of the Kansas Hospital Association.
Politics is likely to remain a barrier in other expansion states, too, especially in ones that would most benefit from it.
Most people who live in the so-called "coverage gap" — meaning they aren't eligible for traditional Medicaid in non-expansion states but make too little for ACA subsidies — live in four states: Texas, North Carolina, Georgia and Florida, where Republicans have opposed the ACA for a decade.
"For states where their legislative leaders have been really dug in against Medicaid expansion its harder for them to unwind that," said Weissfeld.