Republicans are proud to call themselves “the party of Lincoln” in matters of race relations, but inclusion has been a sore point for the party in modern times. A lot's happened since Lincoln's day.
To fully make sense of the often fractious relationship between blacks and the Republican Party, one needs to see how different, ironically, that relationship was not so long ago.
Previously, African Americans flocked to the Republican party, which led the way to Congressional passage of the 13th Amendment to the Constitution — the one outlawing slavery. Republican efforts were also central to passage, in 1866, of a civil rights act that extended full rights to black Americans.
The relationship was generally amicable well into the 20th century, until the administration of Franklin D. Roosevelt.
Under FDR's New Deal in 1936, blacks changed course, voting overwhelmingly for Roosevelt, in part because of a wealth of government spending initiatives, such as work relief programs that benefited blacks during the depths of the Great Depression.