How the ACA has improved healthcare in America
Transforming healthcare access, reducing costs, and expanding coverage for Americans


Introduction
The Affordable Care Act (ACA), signed into law in 2010 by President Barack Obama, fundamentally reshaped the landscape of American healthcare. Aimed at improving access to affordable healthcare, the ACA introduced a range of reforms that expanded coverage, reduced costs, and enhanced the quality of care.
Over a decade since its implementation, the ACA has made significant strides in providing healthcare access to millions of Americans, despite facing political and economic challenges. This report explores the achievements of the ACA in transforming the healthcare system, focusing on its impact on access, affordability, and quality of care.
Expanding healthcare coverage
One of the most significant accomplishments of the ACA was the expansion of healthcare coverage. Prior to its enactment, millions of Americans struggled to afford health insurance, particularly those with pre-existing conditions or who were self-employed. The ACA introduced essential provisions, such as Medicaid expansion and the creation of health insurance marketplaces, which allowed individuals to purchase affordable insurance plans. Medicaid expansion, which extended eligibility to low-income adults in participating states, played a key role in reducing the number of uninsured individuals.
As of 2024, approximately 33 million Americans were covered by Medicaid, a significant increase from 2013, when only about 48 million were enrolled. The expansion also provided comprehensive coverage, ensuring that more Americans received preventive care, emergency services, and treatment for chronic conditions. Medicaid expansion has been particularly impactful for vulnerable populations, including individuals with disabilities, the elderly, and low-income families.
In 2024 open enrollment, a record-setting 21.4 million people selected coverage through the ACA Marketplace. That number has been surpassed in 2025, with nearly 24 million people signing up for Marketplace coverage as of Jan. 8.
The ACA also required that all health insurance plans offered in the individual and small group markets include essential health benefits such as maternity care, mental health services, and prescription drugs. This standardization helped improve the comprehensiveness of insurance coverage, ensuring that Americans received a broad range of services when they needed them most.
Lowering the uninsured rate
The ACA has drastically lowered the uninsured rate in the United States. Prior to its enactment, nearly 16% of Americans were uninsured - a figure that has since fallen to a historic low of 7.7% as of 2023. In states that embraced Medicaid expansion, the decline in uninsured rates has been even more pronounced.
Health insurance marketplaces, established under the ACA, have provided individuals with a centralized platform to compare and purchase insurance plans, often with subsidies to offset costs. These Premium Tax Credits (PTC) are available to individuals earning between 100% and 400% of the federal poverty level, have been instrumental in making healthcare coverage more accessible.
These reductions in the uninsured rate have had a profound impact on public health, as more individuals now have access to preventative care, screenings, and early interventions that can reduce the incidence of severe health conditions and hospitalizations.
Making healthcare more affordable
While the ACA made substantial progress in reducing the number of uninsured Americans, its efforts to address healthcare affordability have seen mixed results. Subsidies provided through the health insurance marketplaces have lowered premium costs for many Americans, particularly those in low-income brackets. A record 93% of ACA marketplace enrollees, or 19.3 million people, received PTCs in 2024. These tax credits:
- Lower the caps on premium contributions for people of all income levels
- Allow people with incomes between 100 and 150% of the poverty level to pay $0 in premiums for "benchmark" silver-level plans; and
- Extend eligibility for PTCs to people with incomes above 400% of the poverty level if their benchmark premiums would exceed 8.5% of household income.
The average enrollee saved an estimated $705 in 2024 because of the PTC enhancements, equivalent to a 44% reduction in premium costs.
The ACA also included provisions to control healthcare spending. For instance, the Medical Loss Ratio (MLR) rule requires insurers to allocate at least 80% of premium revenues to medical care and quality improvement rather than administrative costs or profits. The percentage threshold increases to 85% for large group plans. Insurers that fail to meet this requirement must issue rebates to policyholders, amounting to billions of dollars returned to consumers since the ACA's implementation.
However, challenges persist. Premiums and deductibles have continued to rise in some regions, straining middle-income families who do not qualify for subsidies. A December 2024 analysis from Bloomberg noted that while the ACA has succeeded in expanding coverage, affordability remains a critical issue for many Americans.
Strengthening protections for consumers
The ACA introduced several key consumer protections that have benefited Americans. One of the most notable was the prohibition on insurers denying coverage based on pre-existing conditions. Before the ACA, individuals with conditions like diabetes, asthma, or cancer often faced exorbitant premiums or were denied coverage altogether. With the ACA in place, insurers are required to provide coverage to all applicants, regardless of their medical history.
Furthermore, the ACA made preventive services more accessible by requiring insurance plans to cover preventive care at no cost to the patient. These services, which include vaccinations, screenings, and counseling, have proven essential in reducing the long-term cost of healthcare by addressing health issues early on.
Public opinion and political debate
The Affordable Care Act has had a significant political and cultural impact. While it has undoubtedly expanded healthcare access, it has also been a source of ongoing debate. Early criticism centered around the individual mandate, which was later repealed in 2017. Some critics argued that the ACA's regulations and provisions represented an overreach of federal power, while others felt that it did not go far enough in ensuring universal coverage or controlling costs.
This all came to a head in 2021 when the Supreme Court of the United States upheld (7-2 decision) the ACA, rejecting a third challenge to the healthcare law. After the decision, legal pundits surmised that the ACA was more than ever solidly entrenched in American law. While that has mostly held true, there were still challenges to the ACA in the years to follow.
The most notable was Braidwood Management Inc. v. Xavier Becerra, previously known as Kelley v. Becerra. The case involved Texas District Judge Reed O'Connor, the same judge who previously ruled the ACA unconstitutional without the federal Individual Mandate. On June 21, 2024, a federal appeals court ruled to preserve the ACA's preventive services mandate, which was the crux of the case. However, the U.S. Court of Appeals for the 5th Circuit ruled that the plaintiffs, a group of Christian companies, did not have to comply with the mandate. This opens up the possibility for a broader ruling down the road that could still undermine the mandate nationwide.
Despite these challenges, the ACA's approval has grown over time. A poll by health policy research group KFF found that 6 in 10 U.S. adults had a favorable view of the ACA. This shift reflects growing satisfaction with the ACA's benefits, particularly in light of rising healthcare costs and increasing inequality in access to care. Public opinion has become more favorable as more people benefit from the law's provisions, and the healthcare system continues to evolve.
In the context of the 2024 presidential election, the same KFF poll revealed that unexpected medical bills and healthcare costs top the list of expenses that adults, regardless of partisanship, said they worry about affording.
- three in four adults saying they are "very" or "somewhat worried" about being able to afford unexpected medical bills
- 73% said they worry about the cost of healthcare services for themselves and their family
- 55% report worrying about being able to afford prescription drug costs,
- 48% said they are worried about being able to afford their monthly health insurance premium.
One of the most consistently popular provisions of the Affordable Care Act is its protections for people with pre-existing conditions, the KFF poll found. Most adults across partisans said it is very important that the aspects of the law that prevent health insurance companies from denying coverage due to someone's medical history (67%) and that prevent health insurance companies from charging sick people higher premiums (65%) remain law.
Conclusion
The Affordable Care Act has made a profound impact on American healthcare. Through expanding access to coverage, reducing the uninsured rate, improving affordability, and strengthening consumer protections, the ACA has provided critical support to millions of Americans. While challenges remain, particularly in addressing affordability and ensuring comprehensive coverage for all, the ACA has paved the way for significant improvements in healthcare access and quality. It has withstood past calls for repeal and is poised to withstand future ones, as President Trump is expected to keep the popular healthcare law intact with aims to strengthen it.
As the U.S. continues to grapple with the complexities of healthcare reform, the legacy of the ACA will likely remain central to future discussions about how to provide affordable, high-quality care for all Americans. With ongoing support and continued adaptation, the ACA could serve as a foundation for even greater strides in improving the nation's healthcare system.