Medicaid covers more than 70 million low-income children, pregnant women, adults, seniors, and people with disabilities in the United States. The program represents $1 out of every $6 spent on health care in the US and is the major source of financing for states to provide coverage for the health and long-term needs of low-income residents. President Trump and other GOP leaders have called for fundamental changes in the structure and financing of Medicaid. This brief outlines five key questions to consider as the debate moves forward as well as some potential implications of these changes for states, beneficiaries and providers.