Donald Trump’s recent failed attempt to surprise the political world with a sizable group endorsement by black ministers occasioned a very sharp observation from Joy Reid on The Last Word. After Jonathan Allen noted that Trump was desperately looking for “a racial or ethnic or any other type of minority that he can go to and not already have basically poisoned the well,” Reid helpfully clarified the why of it all: “Republican primary, that’s not about black and Latin voters, because there really aren’t any in the Republican primary,” Reid said. “That’s about white suburban voters who want permission to go with Donald Trump.”

Trump’s situation is anything but unique—it’s just a bit more raw than it is with other Republicans. Ever since the 1960s, as Richard Nixon’s Southern Strategy was being born, there’s been a ongoing dilemma (if not huge contradiction) for the erstwhile “Party of Lincoln” to manage: how to pander just enough to get the racist votes they need, without making it too difficult to deny that’s precisely what they’re doing.

There are a multitude of cover stories involved in facilitating this two-faced strategy, but one of the big-picture ways it gets covered is with a blanket denial: It wasn’t Nixon’s race-based Southern Strategy that got the GOP its current hammerlock on the South, it was something else entirely. Say, the South’s growing affluence, perhaps, or its “principled small-government conservatism,” or the increased “leftism” of the Democratic Party on “social issues”—anything, really, except racial animus. Anything but that. (It’s akin to the widespread beliefs that the Civil War wasn’t fought over slavery, or that the Confederate flag is just a symbol of “Southern pride.”)

Most who make such arguments are simply mired in denial, or worse, but there areseveral lines of argument seemingly based on objective data in the academic literature. But a new National Bureau of Economic Research working paper that Sean McElwee recently referred to should put an end to all that.

“Why did the Democrats Lose the South? Bringing New Data to an Old Debate,” by Ilyana Kuziemko and Ebonya Washington, does three key things: First, it uses previously overlooked data—matching presidential approval against media coverage linking President Kennedy to civil rights—to shed light on a key transition period—broadly, from 1961-1963, narrowly, the spring of 1963—when the Democratic Party clearly emerged as the party of civil rights. Second, it uses another new source of data—responses to the “black president question” (first asked by Gallup in 1958), whether someone would support a black (originally “negro”) candidate for president, if nominated by their party—as a measure of “racial conservatism” to analyze the contrast between the pre- and post-transition periods.

As McElwee reported, the paper “find[s] that racism can explain almost all of the decline of Southern white support for Democrats between 1958 and 2000.” Indeed, it explains all of the decline from 1958 to 1980, and 77% of the decline through 2000. (The authors prefer the 1958-1980 time-frame, since Jesse Jackson’s candidacy in 1984 and 1988 “may have transformed the black president item from a hypothetical question to a referendum on a particular individual.”) Third, the paper looks at the other explanations—the cover stories—and finds they have only a marginal impact, at best. (Although its focus is Southern realignment away from the Democratic Party, the GOP has obviously been gaining strength at the same time as a direct result.) It also sheds light on an early phase of dealignment, starting when Truman first came out for civil rights in 1948, leading to the Dixiecrat revolt. ...