States may choose to adopt the Patient Protection and Affordable Care Act's Medicaid expansion and later decide to drop it, a Centers for Medicare & Medicaid Services official told state legislators yesterday. "Our key message to states is that there's a lot to think through and there's no deadline by which states have to make that determination," said Cindy Mann, director of CMS' Center for Medicaid and CHIP Services, recapping her talk with state officials at a National Conference of State Legislatures summit in Chicago. "We expect and encourage states to look at what their choices are and what their options are. In that regard, we made it clear that the expansion for low-income adults is voluntary with states. That means a state can decide when to come in, if to come in and also, if a state does adopt the expansion and determines at a later time, for whatever reason, that it does not want to maintain the expansion, it could also decide, because it's a voluntary program, to drop the expansion. And we talked about the fact that all other aspects of the law remain intact, including the very favorable federal match rate that's available, and that states need to think through both the costs and the benefits of moving forward." In June, the U.S. Supreme Court ruled the ACA's Medicaid expansion constitutional, but said that the federal government could not withhold all existing Medicaid funds from a state that refuses to participate in the Medicaid expansion.