Abstract As the list of Republican-led states participating in the Medicaid expansion grows, it is becoming increasingly clear that partisanship and ideology alone cannot fully explain states’ choices. This paper examines the political and practical dynamics influencing state Medicaid expansion decisions. Whereas resources and history have served to reinforce the effects of partisanship and ideology, several countervailing forces – including public opinion, interest group pressure, budgetary considerations, and need – are pushing even the reddest states toward expansion. The relative force of these competing pressures within a state can help explain not only whether or not the state expands Medicaid, but also the manner in which it does so, such as through a waiver or executive action. I present five case studies – Nevada, Arizona, Ohio, Arkansas, and Tennessee – to illustrate how these various dynamics are shaping states’ decisions.