Any Republican attempt to replace the Affordable Care Act must address Medicaid, which has literally become the 800-pound gorilla in the health-care policy room. Simply rolling back the ACA’s Medicaid expansion would spike the number of uninsured Americans and expose Congress and the Trump administration to withering criticism. On the other hand, leaving Medicaid unchanged exposes the federal budget to the program’s unsustainable cost trajectory: Federal Medicaid spending has doubled over the past decade.

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