In response to the bill, Barry Goldwater waged a disastrous campaign built in part on his opposition. As NPR put it: “Goldwater can be seen as the godfather (or maybe the midwife) of the current Tea Party. He wanted the federal government out of the states’ business. He believed the Civil Rights Act was unconstitutional — although he said that once it had been enacted into law, it would be obeyed. But states, he said, should implement the law in their own time.” Whites were reassured by the message, but blacks were shaken by it.

Richard Nixon, for whom both Stein and Buchanan would work, helped to seal the deal. Nixon had got nearly a third of the African-American vote in his unsuccessful 1960 bid for the White House, but when he ran and won in 1968 he received only 15 percent. In 1972, he was re-elected with just 13 percent of the black vote. That was in part because the Republican brand was already tarnished among blacks and in part because the Nixon campaign used the “Southern strategy” to try to capitalize on racist white flight from the Democratic Party as more blacks moved into it.

As Nixon’s political strategist Kevin Phillips told The New York Times Magazine in 1970: “The more Negroes who register as Democrats in the South, the sooner the Negrophobe whites will quit the Democrats and become Republicans.”

That’s right: Republicans wanted the Democrats’ “Negrophobes.”

The history of party affiliations is obviously littered with racial issues. But now, there is considerable quarreling and consternation about the degree to which racial bias is still a party trait or motivating political factor for support of or opposition to particular politicians or policies.

It is clear that our politics were “racialized” long before this president came along — and that structure persists — but that’s not the same as saying the voters are racist.

To get more directly at the issue of racism in political parties, Nate Silver’s FiveThirtyEight Politics looked at “a variety of questions on racial attitudes in the General Social Survey” and specifically at “the numbers for white Democrats and white Republicans.”

This wasn’t a perfect or complete measure of racial bias, but more a measure of flagrant bias — the opinions of people aware of their biases and willing to confess them on a survey.