Democrats have herded Blacks into inner city reservations, told them they are there because of racism and kept them voting Democrat for generations. Jessie Jackem'up and others like him have sued the Private Sector employers for billions and produced the situation where a Black employee is about the last thing anybody in business wants, thus helping to keep the Black vote count up there where the Democrats need it to be to survive: 95% Democrat! Listen to the Democrats when they talk to Blacks, they encourage them in hating Whites, they encourage them in being rebellious, in burning cities, etc.. The reason for the high incarceration rate is that welfare just doesn't pay enough, never can, never will, so incomes are subsidized by crime.
Look at how close the elections are in recent history. If that Black vote fell to 50/50 it would be permanently over for Democrats. They will sell the entire economy down the drain to retain those Black votes and they are currently doing just that..