The elephant in the room: why some states are refusing to expand Medicaid

After the US Supreme Court overturned the Affordable Care Act's mandate that states expand Medicaid, roughly half the states have declined to expand. Declining states blame the high state budgetary cost. While these states do have significantly higher expansion costs, they are also significantly more likely to have Republican Party control of the legislature and governor office. Statistical inquiry confirms that after controlling for costs, it is indeed political party control, particularly of the lower chamber of the state legislature that is the most important statistical determinant of state Medicaid expansion decisions.