Why did states argue that the Affordable Care Act’s Medicaid expansion was coercive?

States argued that the Affordable Care Act’s (ACA) Medicaid expansion was coercive because it imposed an onerous financial burden that they were effectively forced to accept to continue receiving federal matching funds for existing Medicaid beneficiaries.1

Although state participation in Medicaid is technically voluntary, the program had become so essential for citizens that states could not realistically opt out. By threatening to withhold all federal Medicaid funds—including those for existing beneficiaries—from states that refused to expand their programs, the federal government created a situation where states had no legitimate choice.12

The Supreme Court ultimately agreed with this assessment in National Federation of Independent Business v. Sebelius (2012). Chief Justice John Roberts characterized the threat to withhold existing funds as a "gun to the head," noting that when the federal government forces states to implement a program by removing any real choice, it undermines the political accountability essential to the U.S. federal system. Consequently, the Court ruled that the Secretary of Health and Human Services could not withhold existing Medicaid funds from states that declined the expansion.23