Why the value judgement on single mothers? Also, the 73% is out of wedlock, not necessarily single mothers. Single mother numbers are actually 67%.
>and huge level of incarceration.
Incarceration policies put in place by republicans and democrats.
>How is it not a failure of political science and Democrats that represent African Americans on all levels of government?
It is a failure of American political policy. However, the answer isn't to build a wall or stop immigration. The answer is to improve education, train people for the jobs that actually exist in our economy, and if all else fails, figure out what we do when there just aren't enough jobs, not just pretend like manufacturing is going to come back. American manufacturing has never produced more goods than the present, but it also employees almost no one, because automation is amazing [1].
[1] Page 4 and 5: http://www.cs.rice.edu/~vardi/workawesome16.pdf