Health Reform in Transition: From Biden’s Expansion to Trump’s Revisions
Tracking how Biden-era marketplace reforms, Medicaid initiatives, and tax provisions reshaped coverage gains — and what early Trump-era policies mean for 2026 and beyond
Abstract
This paper evaluates both the Biden administration’s health care reforms and the Trump Administration’s unraveling of these reforms. The focus is on changes in marketplace, Medicaid, and tax rules impacting the number of people with access to comprehensive health insurance.
Introduction:
The Biden administration entered office in 2021 pledging to build on the Affordable Care Act rather than replace it. It adopted several reforms, leading to the expanded and more affordable coverage through both Medicaid and ACA marketplaces. The Biden-era reforms led to substantial increases in Medicaid and state marketplace insurance and a reduction in the use of short-term plans offering less comprehensive coverage.
Many of the Biden-era health care reforms, which led to expanded use of Medicaid and state-exchange health insurance, are scheduled to be eliminated, either because the provision was scheduled to lapse in the original legislation or has been revered or weakened in the first nine months of the Trump Administration. The impact of these changes on the availability and choice of health insurance coverage has not yet been realized because some law changes have yet to take effect.
The paper considers and evaluates the impacts of both Biden and Trump initiatives on health insurance outcomes.
I. Marketplace Health Insurance Coverage (Biden)
Enhanced ACA Premium Tax Credits.
The American Rescue Plan (ARP, 2021) temporarily enhanced Affordable Care Act premium tax credits by increasing subsidy amounts across the board and removing the prior “subsidy cliff” above 400 percent of the federal poverty level. The Inflation Reduction Act (IRA, 2022) extended these enhancements through plan year 2025.
The policy capped benchmark silver premiums at no more than 8.5 percent of household income with larger subsidies below that level, which lowered net premiums substantially and produced historically high Marketplace sign-ups. Lower-income enrollees often saw zero-dollar premiums, while middle-income households above 400 percent FPL received help for the first time.
The enhancements were written to sunset after 2025 for budget and scoring reasons, and absent further legislation they will lapse for 2026 coverage, causing premiums paid by most subsidized enrollees to jump and reversing some enrollment gains. Analysts and news coverage in 2025 suggest that the likelihood of Congress extending the enhanced ACA premium tax credits beyond 2025 is low.
The Family Glitch.”
Before 2022, individuals were barred from subsidies if a worker’s employer plan was “affordable” for the worker on a self-only basis, even when family coverage was far more expensive. In 2022 the administration finalized an IRS rule that evaluates affordability using the cost of family coverage rather than self-only premiums.
This rule change allows dependents to qualify for Marketplace subsidies when employer family coverage is unaffordable. HHS estimated about one million people gained more affordable coverage through this fix, and independent analyses projected that roughly 200,000 to 400,000 of the newly covered had previously been uninsured.
Simplified Enrollment and Consumer Support.
The administration extended open enrollment to run from November 1 through January 15. It created a monthly special enrollment opportunity for households at or below 150 percent FPL, expanded consumer assistance by restoring and increasing Navigator funding to roughly one hundred million dollars in 2024 and 2025, and standardized plan designs while limiting non-standardized offerings to reduce choice overload and improve out-of-pocket predictability.
DACA Coverage.
A 2024 rule deemed Deferred Action for Childhood Arrivals recipients to be “lawfully present” for purposes of ACA Marketplace and Basic Health Program eligibility beginning November 1, 2024. DACA recipients had previously been excluded from the ACA’s “lawfully present” category and thus ineligible for subsidies despite long-term residence in the United States.
The 2024 rule corrected that exclusion. The Trump Administration is moving to restore the exclusion.
Consumer Protection from Short-Term Limited-Duration Insurance.
Short-term limited-duration insurance (STLDI is a health plan that does not provide the essential minimum benefits offered by ACA compliant health plans on state exchanges or through employers. Unlike state-exchange and employer-based health plans, insurance companies can refuse to sell short-term plans to people with pre-existing conditions and can base premiums on health status. The Biden Administration enacted a rule in 2024 limiting the use of STLDI to an initial terms of three months and a maximum duration of four months including renewals. The rule change also required and required prominent consumer disclosures.
II. Medicaid and CHIP Initiatives (Biden)
The American Rescue Plan (ARP) created a temporary incentive for non-expansion states by adding five percentage points to their overall federal Medicaid matching rate for two years after adoption of Medicaid expansion. This temporary incentive was in addition to the existing matching contributions.
During Biden’s presidency, four states implemented Medicaid expansion:
Oklahoma expanded on July 1, 2021, following a 2020 ballot initiative.
Missouri expanded on October 1, 2021, also pursuant to a 2020 voter-approved initiative but delayed by litigation until court rulings required implementation.
South Dakota expanded on July 1, 2023, after voters approved expansion in a 2022 referendum.
North Carolina expanded on December 1, 2023, after legislative enactment in 2023.
The ARP also created a five-year state option to extend postpartum Medicaid coverage from 60 days to 12 months; Congress later made this option permanent in 2023 legislation, and by early 2025 nearly all states had implemented 12-month postpartum coverage.
Beginning January 1, 2024, federal law requires 12-month continuous Medicaid or CHIP eligibility for children, reducing churn and administrative losses.
As pandemic continuous coverage protections ended, CMS used oversight and enforcement tools to curb inappropriate terminations during unwinding and required states to fix identified systems or procedural problems before disenrolling eligible people.
III. Overall Results Under Biden (2021–2024)
Marketplace enrollment rose to about 24 million plan selections for 2025, an all-time ACA record.
The uninsured rate fell to roughly 7 percent in 2023–2024, down from about 10 percent in 2020, with analyses attributing much of the gain to the enhanced premium tax credits and to Medicaid expansions.
Reliance on short-term plans declined after the 2024 federal limits and disclosures, reducing the risk that consumers would be steered into non-ACA-compliant products.
Coverage gains were particularly pronounced among Hispanic and Black adults, groups that had the highest pre-pandemic uninsured rates.
One limitation of the overall approach was reliance on time-limited provisions, especially the enhanced premium tax credits and temporary Medicaid expansion incentives, which made subsequent policy unraveling easier for a future conservative administration without requiring new legislation.
Trump Administration’s Approach to Health Care (as of September 2025)
I. Marketplace Health Insurance Coverage (Trump)
ACA Subsidies and Scheduled Sunset.
The enhanced ACA premium tax credits remain in place for plan year 2025 and are scheduled to expire for 2026 coverage because the ARP and IRA included sunset dates. Without new legislation, net premiums will rise sharply for subsidized households beginning in 2026, and projections indicate several million more uninsured as subsidies revert to pre-ARP rules.
Family Glitch:
The administration has not taken direct action to reverse the 2022 IRS “family glitch” fix. The IRS rule remains in force, and as of September 2025 there is no active regulatory proposal to undo it.
Simplified Enrollment and Consumer Support:
Navigator Funding Reduction and Timing.
CMS under Trump has eliminated funding and several rules designed to speed up enrollment in state exchanges insurance.
On February 14, 2025, CMS reduced Navigator grants, starting in the 2026 enrollment period, from roughly one hundred million dollars to ten million dollars.
The reduction applies to the next grant period and therefore affects consumer assistance during the 2026 open enrollment period running from November 1, 2025 through January 2026.
CMS issued a final rule effective August 25, 2025 designed to reduce special enrollment privileges currently given to lower income households. The policy changes include shorter open-enrollment periods, an end to automatic reenrollment, and a new $5 fee for households with $0 premiums.
Short-Term Plans Enforcement Posture and Rulemaking.
On August 7, 2025, HHS, Treasury, and Labor announced that they would not prioritize enforcement of the 2024 STLDI duration limits and disclosures while the administration commences rulemaking to revisit the STLDI framework. The 2024 STLDI rule remains on the books, but the immediate enforcement shift signals potential regulatory expansion of short-term plan availability pending a new rule. See Appendix B for a discussion of the effects of increased use of short term health plans.
DACA Coverage Litigation and Regulatory Reversal.
CMS finalized a rule redefining “lawfully present” to exclude DACA recipients effective August 25, 2025, resulting in termination notices for affected enrollees. Litigation is ongoing, and a federal court issued a preliminary injunction shortly before the rule’s effective date that paused parts of the rule in some jurisdictions, while other components proceeded. DACA status renewals continue under separate court orders, but ACA coverage eligibility has been rescinded at the federal level pending litigation outcomes.
II. Medicaid and CHIP (Trump)
The 12-month continuous eligibility requirement for children, effective January 1, 2024, remains in force under statute and has not been repealed by the Trump administration.
The 12-month postpartum Medicaid coverage option made permanent by Congress in December 2022 and largely implemented by states during 2023–2024, continues to be widely available as of September 2025.
Separately, the Trump administration’s One Big Beautiful Bill, signed into law on July 4, 2025. introduces a federal Medicaid work (or community engagement) requirement for able-bodied adults aged 19–64 in expansion populations. Beginning in January 2027, these enrollees must complete at least 80 hours per month of qualifying activities — such as work, job training, education, or volunteering — to maintain Medicaid eligibility. Exemptions apply for certain groups, including pregnant women, individuals with disabilities, and primary caregivers.
III. Overall Results Under Trump (first nine months; timing and lags)
Most initiatives affecting Marketplace eligibility and enrollment timing are structured to apply beginning with plan year 2026 or plan year 2027, and the largest effect on affordability will result from the scheduled expiration of enhanced premium tax credits after 2025. Because of these effective dates and ongoing litigation, coverage levels observed in calendar year 2025 largely reflect Biden-era rules and subsidies.
The visible 2025 changes are primarily the DACA coverage reversal effective August 25, 2025, subject to partial injunctions, and the announced non-enforcement of the 2024 STLDI rule beginning August 7, 2025.
Beginning in 2026, the lapse of enhanced premium tax credits and multiple Marketplace rule changes are expected to reduce enrollment and increase the number of uninsured. Beginning in 2027, the shorter open-enrollment window on the federal platform will further compress sign-up time and may modestly lower plan selections.
Coverage Losses Under Trump — Current and Projected
If enhanced ACA premium tax credits expire after 2025, the Congressional Budget Office projects that about 2.2 million people will lose coverage in 2026, with an average of 3.8 million more uninsured each year from 2026 through 2034.
Marketplace enrollment is expected to fall from about 22.8 million in 2025 to 18.9 million in 2026, and further to 15.4 million by 2030, as average out-of-pocket premiums for subsidized enrollees rise by approximately 75 percent.
Over the longer term, the combined effects of subsidy expiration and recent reconciliation law changes could result in more than 14 million additional uninsured by 2034.
Additional policies under consideration, such as Medicaid work requirements, could increase uninsured rates by 3 percentage points or more in 20 states, with the largest increases (at least 5 percentage points) projected in states such as Louisiana, Florida, and Arizona.
Cuts included in the 2025 “Big Beautiful Bill” are projected to add nearly 12 million uninsured nationally by 2034, including 300,000 more in Texas alone.
Coverage erosion from Trump actions has only just begun.
Conclusion
Biden’s strategy of strengthening the ACA with larger subsidies, consumer protections, Medicaid incentives, and DACA inclusion pushed the uninsured rate to historic lows and set Marketplace enrollment records. The reliance on sunset provisions, however, left major gains dependent on future congressional action.
In the first nine months of the Trump administration, several changes have repealed several of the Biden-era policies, which led to expanded coverage. In some cases, like the elimination of the enhanced premium tax credit, the repeal process did not require any new legislation because it was scheduled to lapse.
A future Democratic or more progressive Administration should consider making its most important policy initiatives permanent, even if the process leading to this result leads to compromises on other issues.
The Trump Administration is phasing in some of their more draconian health care policy changes slowly to delay the impact of these changes past the 2026 and even the 2028 election.
Appendix A: Expanded Note on ACA Subsidies Under Trump
With the enhanced premium tax credits scheduled to sunset after plan year 2025, the Congressional Budget Office projects that millions fewer people will enroll in Marketplace coverage and that the number of uninsured will rise beginning in 2026. KFF estimates that average amounts paid by subsidized Marketplace enrollees would increase by on the order of three-quarters if the enhancements lapse, with especially large increases for middle-income households above 400 percent of poverty who would again face the re-emergence of the subsidy cliff. These estimates are directionally consistent across independent analyses and underscore that the scheduled expiration alone would materially reduce affordability and enrollment even without other regulatory changes.
Appendix B: Short-Term Health Plans and Their Limitations
Short-term limited-duration insurance plans are not required to cover essential health benefits and can exclude pre-existing conditions, impose annual or lifetime dollar caps, omit services such as maternity care and mental health, and rescind coverage after claims are filed. Federal and congressional investigations have documented misleading marketing practices and large gaps in protection, concluding that many consumers purchase these products believing they function like ACA-compliant coverage when they do not. The Biden administration’s 2024 rule curtailed plan duration and required clearer disclosures to mitigate these risks, while the Trump administration has announced non-enforcement pending a new rulemaking that could expand availability again.
A recent report by the Democratic staff of the House Energy and Commerce Committee and a paper by the Kaiser Family Foundation identify several recurring problems with short-term limited-duration health plans.
These include denials of benefits for life-saving procedures such as cancer treatments and heart surgery. Plans impose strict limits on reimbursements for hospital stays, surgeries, and physician services. Typical limits cited include $500 per policy period for doctor visits, a $1,000 daily cap on hospital reimbursement, a $500 maximum for emergency services, and a $2,500 maximum for surgical services.
Consumers have also faced denial of benefits through post-claim underwriting, in which extensive documentation is required after a procedure is conducted, sometimes leading to rescission of coverage. Unlike ACA-compliant coverage, short-term plans are not guaranteed renewable under federal law. They often impose annual and lifetime benefit caps, lack annual caps on cost sharing, and are not subject to the ACA’s minimum medical loss ratio of 80 percent.
The Kaiser Family Foundation reviewed the scope of benefits under short-term plans and found significant exclusions. Forty-three percent of plans lacked coverage for mental health services, 62 percent did not cover substance abuse treatment, 71 percent did not cover outpatient prescription drugs, and none covered maternity care. In seven states, all available short-term plans lacked coverage in each of these categories.
Other analyses have highlighted gaps with serious financial consequences. The University of Michigan’s Institute for Healthcare Policy and Innovation (IHPI) reported that increased reliance on short-term plans worsens coverage gaps for pregnant women. A report by the Center on Budget and Policy Priorities, citing research from the American Cancer Society Action Network, estimated that a patient diagnosed with breast cancer while covered by a short-term plan could face $40,000 to $60,000 in out-of-pocket costs compared with under $8,000 for a comparable ACA Marketplace enrollee.
Case studies illustrate the human cost. The House Energy and Commerce report described a patient who received a $14,000 bill for a two-day pneumonia hospital stay, and another who received only $7,000 toward a $35,000 emergency procedure bill, leaving $28,000 in uncovered costs. These examples underscore how short-term plans can leave patients facing catastrophic expenses despite nominally having insurance coverage.
Appendix C: Sources and Key References
KFF. “Inflation Reduction Act Health Insurance Subsidies — Impact and What Happens if They Expire” (July 26, 2024).
KFF. “A Look at ACA Coverage Through the Marketplaces and Medicaid Expansion Ahead of Potential Policy Changes” (January 15, 2025).
U.S. Department of Health and Human Services (HHS). “Record-Breaking 2025 Open Enrollment” (January 8, 2025).
Internal Revenue Service (IRS). “Treasury Department Finalizes Rule to Fix ‘Family Glitch’” (October 2022).
Centers for Medicare & Medicaid Services (CMS). “Short-Term, Limited-Duration Insurance — Final Rule” (April 2024).
KFF. “Medicaid Postpartum Coverage Extension Tracker” (accessed 2025).
Medicaid.gov. “Continuous Eligibility for Children in Medicaid and CHIP” (effective January 1, 2024).
KFF. “Status of State Medicaid Expansion Decisions: Interactive Map” (updated August 2025).
Federal Register. CMS guidance on Medicaid unwinding and renewal processes (December 6, 2023).
HealthCare.gov. “DACA and the Health Insurance Marketplace” (updated 2025).
American Hospital Association (AHA). “Federal Agencies Signal Shift in Enforcement of Short-Term Health Insurance Rules” (August 8, 2025).
Politico. “Health Industry Lobbying for Subsidy Extension” (August 28, 2025).
U.S. House of Representatives, Committee on Energy & Commerce (Majority Staff). “Shortchanged: How Short-Term Health Insurance Plans Leave Patients at Risk” (2020).
KFF. “Understanding Short-Term Limited Duration Health Insurance Plans” (2020).
University of Michigan IHPI. “Coverage Gaps for Pregnant Women and Short-Term Health Plans” (2021).
Center on Budget and Policy Priorities (CBPP). “Short-Term Health Plans Expose Patients to Catastrophic Costs” (citing ACS CAN research, 2020).
CMS. “2024 and 2025 Notice of Benefit and Payment Parameters Fact Sheets.”
Reuters (2025). Coverage of preliminary injunction orders on Marketplace rules and DACA.
Congressional Budget Office (CBO). “Budgetary Effects of Health Coverage Subsidy Expiration” (December 2024).
KFF. “How Much More Would People Pay in Premiums if the ACA’s Enhanced Subsidies Expired?” (2024).
KFF. “How Will the 2025 Reconciliation Law Affect the Uninsured Rate in Each State?” (2025).
American Hospital Association (AHA). “CBO: 2.2 Million Consumers Will Lose Insurance in 2026 if ACA Enhanced Premium Subsidies Expire” (December 2024).
Houston Chronicle. “Texas Medicaid Cuts in ‘Big Beautiful Bill’ Could Leave 300,000 More Uninsured” (2025).