The first, by the political scientist Larry Bartels, analyzed the move of the white working class away from Democrats, a move made famous in Thomas Frank’s “What’s the Matter With Kansas?” Mr. Frank argued that working-class whites were being induced to vote against their own interests by the right’s exploitation of cultural issues. But Mr. Bartels showed that the working-class turn against Democrats wasn’t a national phenomenon — it was entirely restricted to the South, where whites turned overwhelmingly Republican after the passage of the Civil Rights Act and Richard Nixon’s adoption of the so-called Southern strategy.

And this party-switching, in turn, was what drove the rightward swing of American politics after 1980. Race made Reaganism possible. And to this day Southern whites overwhelmingly vote Republican, to the tune of 85 or even 90 percent in the deep South.

The second paper, by the economists Alberto Alesina, Edward Glaeser, and Bruce Sacerdote, was titled “Why Doesn’t the United States Have a European-style Welfare State?” Its authors — who are not, by the way, especially liberal — explored a number of hypotheses, but eventually concluded that race is central, because in America programs that help the needy are all too often seen as programs that help Those People: “Within the United States, race is the single most important predictor of support for welfare. America’s troubled race relations are clearly a major reason for the absence of an American welfare state.”

Now, that paper was published in 2001, and you might wonder if things have changed since then. Unfortunately, the answer is that they haven’t, as you can see by looking at how states are implementing — or refusing to implement — Obamacare.

For those who haven’t been following this issue, in 2012 the Supreme Court gave individual states the option, if they so chose, of blocking the Affordable Care Act’s expansion of Medicaid, a key part of the plan to provide health insurance to lower-income Americans. But why would any state choose to exercise that option? After all, states were being offered a federally-funded program that would provide major benefits to millions of their citizens, pour billions into their economies, and help support their health-care providers. Who would turn down such an offer?