Medicaid, national health insurance program in the United States for low-income persons and persons with disabilities. It was established in 1965 with passage of the Social Security Amendments and is now run by the Centers for Medicare and Medicaid Services. In 2010 the program was expanded as part of heath insurance legislation, to provide insurance for low-income people not eligible for subsidies under the new law, but the expansion was made voluntary for the states, and only about half the states elected to participate in the expansion (effective 2014). The federal role in Medicaid is limited to setting standards, issuing regulations and guidelines, and overseeing operation of the program by the states. More than 58 million people received Medicaid in 2013. Of the various services covered under Medicaid, about half of the funds are used to purchase in-patient hospital services and nursing home services; the remainder covers physician services, drugs, laboratory services, X rays, and other services. Political debate on the future of Medicaid has accompanied health-care reform and budget deficit reduction debates.