Ten states still have not expanded Medicaid under the Affordable Care Act, leaving roughly 1.4 million adults in a “coverage gap” where they earn too much for traditional Medicaid but too little to qualify for marketplace insurance subsidies. The reasons are overwhelmingly political, rooted in partisan opposition to the ACA itself, though state leaders have framed their objections in terms of fiscal responsibility, government overreach, and philosophical disagreements about the role of public insurance.
The Supreme Court Made Opting Out Possible
When the ACA passed in 2010, Medicaid expansion was designed to be mandatory for all states. The federal government would cover nearly all of the cost, and states that refused risked losing their existing Medicaid funding. In 2012, the Supreme Court’s ruling in National Federation of Independent Business v. Sebelius changed that. The Court ruled that the federal government could not threaten to pull existing Medicaid dollars from states that declined to expand, effectively making expansion optional.
Within two years of the law’s passage, partisan opponents had consolidated power in state legislatures across the country. What followed was a state-by-state political battle that continues today.
Partisan Opposition Drove Most Decisions
The single strongest predictor of whether a state expanded Medicaid is which party controlled its government. In states where Republican control was strong, elected officials rejected what amounted to nearly full federal funding for expansion, along with other ACA-related grants. Health Affairs research found that these decisions were “often the product of partisan and ideological incentives rather than deliberate reasoning about how policy affects population health.”
The arguments varied in their specifics but shared common themes. Opponents warned that expansion would grow government dependency, burden state budgets once federal funding rates decreased, and entrench a law they had voted against and campaigned on repealing. What might otherwise have been routine policy discussions about income thresholds and eligibility rules became, as Health Affairs put it, “philosophical debates over ‘big government.'”
Some governors found creative middle paths. Wisconsin’s Scott Walker, a Republican, renegotiated an existing Medicaid waiver to cover more low-income residents without formally accepting the ACA expansion. This allowed him to claim he had reduced the state’s uninsured population by over 224,000 people while still symbolically rejecting the law. Several states that did expand under Republican governors, including Arkansas, Kentucky, and New Hampshire, later sought to add work or community engagement requirements as a condition of expanded eligibility, signaling continued ideological discomfort with the program’s scope.
Which States Still Haven’t Expanded
As of 2025, 41 states (including Washington, D.C.) have adopted the Medicaid expansion. The ten holdouts are Florida, Georgia, Kansas, Mississippi, South Carolina, Texas, Tennessee, Wisconsin, and Wyoming. These are predominantly states with Republican-controlled legislatures and governors who have maintained opposition since 2010.
In several cases, voters have tried to force the issue through ballot initiatives. States like Idaho, Nebraska, Utah, Maine, Missouri, Oklahoma, and South Dakota all expanded Medicaid after voters approved ballot measures, often over the objections of their state legislatures. In the remaining holdout states, no such mechanism has succeeded, and legislative leadership has blocked expansion proposals from advancing.
The Financial Incentives States Turned Down
The federal government has offered increasingly generous terms to encourage expansion. Under the original ACA structure, the federal government covered 100% of costs for newly eligible enrollees from 2014 through 2016, gradually stepping down to 90% by 2020, where it remains. For context, the federal government covers only about 50% to 77% of costs for traditional Medicaid populations, depending on the state. Expansion came at a dramatically better deal.
In 2021, Congress sweetened the offer further through the American Rescue Plan Act. States that hadn’t yet expanded were offered a 5-percentage-point increase to their regular federal matching rate for all existing Medicaid spending, not just expansion costs, for two years. For large states like Texas and Florida, this meant billions of dollars in additional federal funding for programs they were already running. Even so, no remaining holdout state took the deal.
The Coverage Gap This Created
The ACA was designed as an interlocking system. Medicaid would cover everyone up to 138% of the federal poverty level (about $21,600 a year for an individual in 2025), and marketplace subsidies would help everyone above that threshold afford private insurance. When states opted out of expansion, they broke that link.
In non-expansion states, traditional Medicaid eligibility for adults is often extremely limited. Many of these states only cover parents with incomes well below the poverty line and exclude childless adults entirely, regardless of how poor they are. A single adult earning $10,000 a year in Texas, for example, likely earns too much for Medicaid but falls below the poverty line where marketplace subsidies begin. That person has no affordable coverage option at all.
Today, 1.4 million uninsured adults are trapped in this gap. An additional 1.3 million uninsured adults with incomes between 100% and 138% of the poverty level would also gain coverage if all states expanded, bringing the total to roughly 2.7 million people who could be covered.
Health and Economic Consequences
The decision to opt out has had measurable effects on both health outcomes and healthcare infrastructure. A study published in The Lancet Public Health, tracking data from 2010 to 2018, found that Medicaid expansion was associated with a reduction of nearly 12 deaths per 100,000 adults compared to non-expansion states. The researchers noted that the full health benefits of expansion, particularly for conditions like heart disease and cancer, take several years to materialize because preventive measures like cholesterol-lowering medications and cancer screenings need time to produce results.
Rural hospitals have been hit especially hard. Between 2014 and 2024, 69% of rural hospital closures occurred in states that had not expanded Medicaid. Without expansion, hospitals in these states absorb more uncompensated care from uninsured patients while receiving less Medicaid revenue to offset those costs. Half of all rural hospitals in non-expansion states had negative operating margins in 2023, compared to 41% in expansion states. In the most isolated rural areas, far from any metro area, the gap was even wider: 59% of hospitals in non-expansion states were losing money, versus 45% in expansion states.
These closures don’t just affect uninsured residents. When a rural hospital shuts down, everyone in the surrounding area loses access to emergency care, labor and delivery services, and routine medical visits, regardless of their insurance status.
Why Holdout States May Continue to Resist
For the remaining ten states, the calculus has not changed significantly despite over a decade of evidence and financial incentives. The political identity of opposing the ACA has become deeply embedded in these states’ Republican leadership. Accepting expansion would mean embracing a law that many of these officials built careers opposing, and primary elections in these states tend to punish that kind of reversal.
There are also genuine, if debatable, fiscal concerns. While the federal government covers 90% of expansion costs, the remaining 10% still represents real money for state budgets. States like Mississippi and Kansas, which already face tight budgets, worry about long-term sustainability, particularly if Congress ever reduces the federal match rate. Critics of this argument point out that expansion states have generally seen net budget savings because newly insured residents use less emergency care and other state-funded services, but that evidence has not shifted the political dynamics in holdout states.
The result is a patchwork system where your access to health coverage depends heavily on which state you live in, a gap that has persisted for over a decade with little indication it will close soon in the remaining holdout states.