As the debate over the future direction of our health care system heats up leading into the 2020 Presidential election, several Democratic proposals to create a single, federal, universal health insurance program known as Medicare-for-all have garnered significant attention. These proposals would replace most current public and private health insurance with a new federal program that would guarantee health coverage for all or nearly all U.S. residents. However, many details about how a new public program would be implemented and financed are not yet known. While much attention has focused on the implications of ending private insurance and Medicare, the debate has largely ignored the effects on the low-income and vulnerable populations covered by Medicaid and the broader implications for states of eliminating the Medicaid program.