If this overview in The Wall Street Journal reflects the content, though, it seems fairly banal. As everyone with any awareness of American political history knows, for about 100 years starting in the mid-19th century, the Democratic Party was the vehicle of choice for the white supremacist agenda that dominated the politics of the white south and that vast majority of the leading villains in the story of race in America were Democrats. That said, starting in the New Deal, the Democrats also became the preferred party of urban northern African-Americans and white liberals. That created a lot of intra-party tensions which played out over the next 30–40 years and resulted in a decisive victory for the racial liberals.
Meanwhile, in a parallel development, “new right” insurgents — most of whom were, like Barry Goldwater and Ronald Reagan, opponents of civil rights legislation — took control of the Republican Party. During this time, the white south became the electoral base of the GOP, while the much-shrunken Dixie faction of the Democratic Party became biracial. I don’t think there’s anything about this history that would upset modern-day Democrats — obviously, Abe Lincoln and the GOP was the right way to go in the 1860s and Woodrow Wilson’s record on racial issues was terrible but that was all quite a long time ago.