The Affordable Care Act (ACA) expanded Medicaid eligibility, but due to a 2012 U.S. Supreme Court ruling, the expansion is optional for states. As of 2014, about half the states have elected to expand Medicaid eligibility. In states that adopted the expansion, all citizens with incomes below 138% of the federal poverty level will be eligible. Because states had different eligibility criteria prior to expansion, the demographic characteristics of newly eligible individuals will vary from state to state. Although states must include coverage of the ACA’s essential health benefits for their Medicaid expansion populations, federal regulations allow states to develop unique benefits subject to approval by federal officials, and many states have chosen that option.