Tallying up state decisions on the Medicaid expansion is a bit of a squishy science. States don't have to make any official declarations, so we have to rely on what governors pledge. That doesn't necessarily predict the future. Take Missouri, for example: Democratic Gov. Jay Nixon has pledged to participate in the Medicaid expansion...but still needs funding from Missouri's Republican-controlled legislature to move forward.
Florida's Republican Gov. Rick Scott, on the other hand, had come out squarely against the expansion but has recently shown some openness to the idea.
What we do know for sure is this: The Medicaid expansion still breaks down along partisan lines. We haven't seen one Republican governor decide to expand nor one Democrat decide not to.
It's also worth keeping in mind that the number of states that participate in the Medicaid expansion isn't a great measure at all of how many Americans will enroll. The states that have opted out are a lot bigger than those who have opted in. In Vermont, which has signed up for the expansion, the Kaiser Family Foundation expects that 3,000 residents will gain coverage. In Texas, which has rejected the provision, that number stands at 1.8 million.
All told, the nine states that have decided to opt out would be expected to cover more Americans than the 17 states that have opted in. The Kaiser Family Foundation estimates enrollment would be 4.3 million among the opt-in states, compared with 5.3 million among the opt-outs. Much of that difference is explained by the fact that the states who have opposed the provision tend to have less expansive Medicaid programs, meaning the Affordable Care Act expansion would have an even greater impact.