Proof positive that gender simply doesn't matter if you are the best at what you do.
Probably nobody has suffered more vile attacks than Clarence Thomas[2] for the crime of being Republican while black. To be an inspirational black politician, you must be liberal.
[1]http://www.theatlantic.com/politics/archive/2012/12/tim-scot...
[2]http://www.time.com/time/magazine/article/0,9171,134324,00.h...
[2]http://www.weeklystandard.com/blogs/new-tone-naacp-silent-ra...
[2]http://rightpunditry.files.wordpress.com/2013/02/judge-c-tho...
http://www.factcheck.org/bushs_16_words_on_iraq_uranium.html
There's probably no-one truly objective on the subject, as politics are entwined in every aspect... but Clarke worked under four administrations. Tenet's book sheds light on the subject as well.
While some were truly evil, I tend to believe that Bush wanted to believe it enough that he convinced himself of it. The human mind is a subject of its own.
Liberals are not destroying the credibility of black republicans, the black community has a profoundly negative view of black republicans.