Medicaid is the health insurance safety net program in the United States of America. Enrollment has soared over the past decade, especially after the Affordable Care Act of 2014 expanded eligibility to millions of low-income working-age adults. The expansion reduced the proportion of uninsured adults of this age from 33% to 17%, improving access to and affordability of health care. In its first four years, it saved an estimated 20,000 lives and increased the number of insureds by more than 20 million. Today, Medicaid covers about one in five people in the US. New provisions in the One Big Beautiful Bill Act (H.R.1) introduce inefficiencies and administrative hurdles that could reverse this progress. The program's growth has come with controversy over its purpose and financial sustainability.