The fix is in
Henry Louis Gates Jr. explains that because of redistricting and racial gerrymandering, congressional elections in most districts are rigged in favor of one party or the other. And racial gerrymandering, while creating majority-black districts, has marginalized blacks left in majority-white districts:
The creation of black-majority districts was necessary when the Democratic Party had a monopoly in the South, and whites would almost never vote for blacks. But since 1990, districting deals between Republicans and black Democrats have led to political mischief. Shepherding black voters into black districts left other districts lily-white - and skewed to the right. You saw the consequences in 1994, when the House came under Republican control.