evidence: States that have not implemented the expansion have uninsured rates that are nearly double the rate of expansion states (14.1% compared to 7.5%). People without insurance coverage have worse access to care than people who are insured. One in five uninsured adults in 2022 went without needed medical care due to cost and uninsured people are less likely than those with insurance to receive preventive care and services for major health conditions and chronic diseases. [...] If all states adopted the Medicaid expansion, approximately 2.9 million uninsured adults would become newly eligible for Medicaid. This number includes the 1.5 million adults in the coverage gap and an additional 1.4 million uninsured adults with incomes between 100% and 138% FPL, most of whom are currently eligible for Marketplace coverage but not enrolled (Figure 7 and Table 1). Most of the adults who are currently eligible for coverage in the Marketplace qualify for plans with zero premiums; however, even with no premiums, Medicaid could provide more comprehensive benefits and lower cost-sharing compared to Marketplace coverage. The potential number of people who could be reached by Medicaid expansion varies by state.