The Affordable Care Act (ACA) was initially expected to provide coverage for 32 million uninsured individuals and families when fully implemented. About half of the newly covered were expected to obtain private coverage, while the other half would enroll in an expanded Medicaid program. The ACA contains financial incentives designed to strongly encourage states to expand Medicaid eligibility. The Obama administration, and advocates for the poor, and have touted the benefits of expanding Medicaid: The federal government promises to pay most costs for those newly eligible. However, a thorough discussion of the costs, obstacles, alternatives and potential pitfalls is critically important.