The Trump administration's Healthy Adult Opportunity waiver follows a long history of Republican attempts to retrench the Medicaid program through block grants and to markedly reduce federal spending while providing states with substantially greater flexibility over program structure. Previous block grant proposals were promulgated during the presidential administrations of Ronald Reagan and George W. Bush and majorities in Congress led by House Speaker Newt Gingrich and House Budget Committee Chair and then Speaker Paul Ryan. Most recently, Medicaid block grants featured prominently in Republican efforts to repeal and replace the Affordable Care Act. This essay traces the history of Republican Medicaid block grant proposals, culminating in the Trump administration's Healthy Adult Opportunity initiative. It concludes that the Trump administration's attempt to convert Medicaid into a block grant program through the waiver process is illegal and, if implemented, would leave thousands of people without necessary medical care. This fact, combined with failed legislative efforts to block grant Medicaid during the last forty years, highlights the substantial roadblocks to radically restructuring a popular program that helps millions of Americans.