Millions of Americans are getting health insurance because of Obamacare. But you’re a lot less likely to be among them if you live in one of the “red” states than if you live in one of the “blue” states—and there’s no great mystery why.

It’s because the conservative officials who run most of the red states want it that way.

You can see that pattern clearly in new reports on the Affordable Care Act that became available last week. They come from surveys demonstrating that the law is thinning the ranks of the uninsured across the country. But two of the reports—one from the Commonwealth Fund, the other from the Urban Institute—broke down the data by state and found a striking, if predictable, disparity.

Officials in states like California, Maryland, and Michigan have done just what Obamacare called upon them to do. They have opted to expand their Medicaid programs, so that all low-income people are eligible. Officials in other states, including Florida, Missouri, and Texas, have refused to expand their programs. To be eligible for Medicaid in one of those states, you have to fall into a special category, like low-income pregnant women, who were eligible before.