The
Social Security Amendments of 1965 created Medicaid by adding
Title XIX to the
Social Security Act. Under the program, the federal government provided matching funds to states to enable them to provide Medical Assistance to residents who met certain eligibility requirements. The objective was to help states assist residents whose income and resources were insufficient to pay the costs of traditional commercial health insurance plans. By 1982, all states were participating. The last state to do so was Arizona. The
Medicaid Drug Rebate Program and the
Health Insurance Premium Payment Program (HIPP) were created by the
Omnibus Budget Reconciliation Act of 1990 (OBRA-90). This act helped to add Section 1927 to the Social Security Act of 1935 and became effective on January 1, 1991. This program was formed due to the costs that Medicaid programs were paying for discount price outpatient drugs. The
Omnibus Budget Reconciliation Act of 1993 (OBRA-93) amended Section 1927 of the Act, bringing changes to the Medicaid Drug Rebate Program. Medicaid also offers a Fee for Service (Direct Service) Program to schools throughout the United States for the reimbursement of costs associated with the services delivered to students with
special education needs. Federal law mandates that children with disabilities receive a "free appropriate public education" under Section 504 of The Rehabilitation Act of 1973. Decisions by the United States Supreme Court and subsequent changes in federal law require states to reimburse part or all of the cost of some services provided by schools for Medicaid-eligible disabled children.
Expansion under the Affordable Care Act by state: The
Affordable Care Act (ACA), passed in 2010, substantially expanded the Medicaid program. Before the law was passed, some states did not allow able-bodied adults to participate in Medicaid, and many set income eligibility far below the Federal poverty level. Under the provisions of the law, any state that participated in Medicaid would need to expand coverage to include anyone earning up to 138% of the Federal poverty level beginning in 2014. The costs of the newly covered population would initially be covered in full by the Federal government, although states would need to pay for 10% of those costs by 2020. However, in 2012, the Supreme Court held in
National Federation of Independent Business v. Sebelius that withdrawing all Medicaid funding from states that refused to expand eligibility was unconstitutionally coercive. States could choose to maintain pre-existing levels of Medicaid funding and eligibility, and some did; over half the national uninsured population lives in those states. As of March 2023, 40 states have accepted the
Affordable Care Act Medicaid extension, as has the
District of Columbia, which has its own Medicaid program; 10 states have not. Among adults aged 18 to 64, states that expanded Medicaid had an uninsured rate of 7.3% in the first quarter of 2016, while non-expansion states had a 14.1% uninsured rate. The
Centers for Medicare and Medicaid Services (CMS) estimated that the cost of expansion was $6,366 per person for 2015, about 49 percent above previous estimates. An estimated 9 to 10 million people had gained Medicaid coverage, mostly low-income adults. The Kaiser Family Foundation estimated in October 2015 that 3.1 million additional people were not covered in states that rejected the Medicaid expansion. In some states that chose not to expand Medicaid, income eligibility thresholds are significantly below 133% of the poverty line. Some of these states do not make Medicaid available to non-pregnant adults without disabilities or dependent children, no matter their income. Because subsidies on commercial insurance plans are not available to such individuals, most have few options for obtaining any medical insurance. For example, in
Kansas, where only non-disabled adults with children and with an income below 32% of the poverty line were eligible for Medicaid, those with incomes from 32% to 100% of the poverty level ($6,250 to $19,530 for a family of three) were ineligible for both Medicaid and federal subsidies to buy insurance. Several states argued that they could not afford the 10% contribution in 2020. Some studies suggested that rejecting the expansion would cost more due to increased spending on uncompensated
emergency care that otherwise would have been partially paid for by Medicaid coverage. A 2016 study found that residents of
Kentucky and
Arkansas, which both expanded Medicaid, were more likely to receive health care services and less likely to incur emergency room costs or have trouble paying their medical bills. Residents of
Texas, which did not accept the Medicaid expansion, did not see a similar improvement during the same period. Kentucky opted for increased managed care, while Arkansas subsidized private insurance. Later, Arkansas and Kentucky governors proposed reducing or modifying their programs. From 2013 to 2015, the uninsured rate dropped from 42% to 14% in Arkansas and from 40% to 9% in Kentucky, compared with 39% to 32% in Texas. A 2016
DHHS study found that states that expanded Medicaid had lower premiums on exchange policies because they had fewer low-income enrollees, whose health, on average, is worse than that of people with higher income. The
Census Bureau reported in September 2019 that states that expanded Medicaid under ACA had considerably lower uninsured rates than states that did not. For example, for adults between 100% and 399% of poverty level, the uninsured rate in 2018 was 12.7% in expansion states and 21.2% in non-expansion states. Of the 14 states with uninsured rates of 10% or greater, 11 had not expanded Medicaid. The ACA was structured with the assumption that Medicaid would cover anyone making less than 133% of the Federal poverty level throughout the United States; as a result, premium tax credits are only available to individuals buying private health insurance through
exchanges if they make more than that amount. This has given rise to the so-called
Medicaid coverage gap in states that have not expanded Medicaid: there are people whose income is too high to qualify for Medicaid in those states, but too low to receive assistance in paying for private health insurance, which is therefore unaffordable to them.
Medicaid work requirements A federal judge blocked Medicaid work requirements in Arkansas and Kentucky on March 27, 2019, ruling that the mandates undermined Medicaid's core purpose of providing health care to the needy. U.S. District Judge
James Boasberg found that the requirements created obstacles to coverage and had been improperly approved by federal officials.
2025 Medicaid cuts in the second Trump administration In 2025, Republican Congressional leaders
John Thune and
Mike Johnson announced goals of cutting 1.5 to 2 trillion dollars of the
US federal budget, with President
Donald Trump stating that cuts to Medicaid would only include "abuse or waste". The 2025
budget resolution, which was passed by the House of Representatives with only Republicans votes, proposed cutting $880 billion from the Standing Committee for Energy and Commerce, which includes many areas, such as Medicaid and Medicare. On July 4, 2025, President Donald Trump signed the
One Big Beautiful Bill Act, intended in part to implement this resolution. The act cut Medicaid in a number of ways: while it did not repeal the ACA's Medicaid expansion, it mandated work requirements for able-bodied Medicaid recipients. It also requires Medicaid recipients above the
federal poverty line to pay more fees for coverage; adds new verification requirements; increases the number of times states need to check the eligibility of their Medicaid expansion recipients; prohibits Medicaid from funding nonprofits that provide
abortion care; makes it harder for
illegal immigrants to use Medicaid; bans
pharmacy benefit managers from using spread pricing; and puts limits on so-called "provider taxes" that states impose on healthcare providers to fund their portion of Medicaid spending. The non-partisan
Congressional Budget Office (CBO) estimated that it will reduce the number of people on Medicaid by several million.; the CBO estimates that the work requirements in particular will lead 11 million to lose their Medicaid coverage, many of whom already work or qualify for exemptions but will not be able to get through the
red tape. The bill prompted claims that undocumented immigrants are on Medicaid. Undocumented immigrants are already ineligible for full Medicaid benefits, and many undocumented immigrants access state-funded health programs rather than federal Medicaid. According to a CBO analysis, the bill's provisions could lead some states to cut back those state-funded health programs, potentially causing an estimated 1.4 million people to lose state-level health coverage, including undocumented immigrants. When commenting on the Trump administration's
One Big Beautiful Bill Act and the impact of the Medicaid provisions on the economy,
USDA Secretary
Brooke Rollins stated that 34 million able-bodied adults on Medicaid should be working. According to the Government Accountability Office, roughly 70% of Medicaid recipients already work at least 35 hours per week but still qualify due to low wage. == State implementations ==