Why Do Black People Vote For Democrats?

As recently as 1956, nearly 39 percent of blacks voted Republican in that year's presidential election. After the Civil War, Abe Lincoln's Republican Party easily carried the black vote -- where blacks were allowed to vote. Unwelcome in the Democratic Party, most blacks voted Republican and continued to do so through the early part of the 20th century. It wasn't until 1948, when 77 percent of the black vote went to Harry Truman, who had desegregated the military, that a majority of blacks identified themselves as Democrats.

Yet, as a percentage of the party, more Republicans voted for the passage of the Civil Rights Act of 1964 than did Democrats. Why do black people vote for democrats?