Why is America the only wealthy nation that doesn’t guarantee essential health care for all? (We’ve made a lot of progress under Obamacare, but not enough, and the Trump administration is doing its best to kill it.) Why do we have much higher poverty than our economic peers, especially among children, and much higher infant mortality despite the sophistication of our medical system?

The answer, of course, comes down to politics: We are uniquely unwilling to take care of our fellow citizens. And behind that political difference lies one overwhelming fact: the legacy of slavery. All too often, white Americans think of the social safety net not as something for people like themselves fallen on hard times, but as a giveaway to Those People.

This isn’t idle speculation. If you want to understand why policies toward the poor are so different at the state level, why some states offer so much less support to troubled families with children, one predictor stands out: the African-American share of the population. The more blacks, the less compassion white voters feel.

The story gets even clearer if you look at the implementation of the Affordable Care Act, which allows states to expand Medicaid coverage at federal expense — that is, to provide health insurance to a large fraction of the population at no cost. You might think that this was a no-brainer, and so far 31 states and the District of Columbia have taken advantage of this opportunity. But only two of those states are among the 11 that seceded in 1861 to form the Confederacy.