A new study by Jonathan Gruber, one of the ACA’s chief architects, suggests that roughly two-thirds of new Medicaid enrollees in 2014 were eligible for the program under previous state eligibility criteria—meaning that they were not made eligible by the ACA. Gruber’s results, combined with much higher than expected Medicaid enrollment and spending over the past three years, has profound implications for the distribution of program costs and the effect of a repeal of the ACA. This means that the federal government has likely paid billions more each year than the law allows for the expansion population while states have spent billions less. Additionally, Gruber’s results suggest that if the ACA were repealed, a lot fewer people would likely lose coverage than previously thought.

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