States can cite a lot of reasons for not implementing the health-care law: It's an overwhelming amount of work, their residents don't like it, and it's pretty expensive. But the best explanation for a state's resistance to Obamacare, a new research suggests, tends to be its politics.

George Washington University's Elizabeth Rigby paper coming out this week in The Forum: A Journal of Applied Research in Contemporary Politics that looked at what can best predict a state's resistance to the health care law. She looked at a whole bunch of reasons, like the magnitude of change: The amount that states would have increase Medicaid enrollment, for example, as well as the capacity of state government to handle those changes.

She also looked at the political control of each state, considering the party affiliation of governors, attorney generals and insurance commissioners (all of which tend to play big roles in implementing the health law).

She looked at how well all those factors predicted a state's resistance to the health care law (measured by those who have filed lawsuits against it, passed legislation and turned grants). As you can see below, the best predictor was the politics of the state:

"Resistance is higher in states with greater public opposition and in those states that are asked to make more drastic changes in terms of expanding citizen access to health insurance," Rigby concludes. "Yet the driving factor behind opposition to the reform was found to be the partisan affiliation of state elected officials - with greater resistance seen in states in which either the legislative or executive branch were controlled by the Republican party."

There is one other way to think about Rigby's findings that's worth pointing out. Republican elected officials tend to have different policy preferences about how to move forward on health reform; you can get a good sense of that by reading through some of the letters that the Republican Governor's Association has fired off to the Obama administration in recent months. As much as this study points to political disagreement, it could also highlight a policy dispute over the best way to move forward on reforming our health care system.