The thought of rallying behind a conservative African-American candidate for the Republican nomination undoubtedly is appealing to many conservatives, if only to prove to liberals and journalists that they aren’t the racists they are often portrayed to be.

Just as important, many Republicans understand that black conservatives and conservative women drive Democrats up the wall. So supporting Cain is a way for conservative Republicans to get just an extra bit of satisfaction knowing how it rattles their opponents. (Former San Francisco Mayor Willie Brown once called Supreme Court Justice Clarence Thomas “a shill and cover for the most insidious form of racism.”)

This isn’t to suggest that conservatives are embracing Cain because he is black. Perennial African-American candidate Alan Keyes never made much of a splash during his presidential bids, and if Cain’s race were such an important factor to Republicans, they would have embraced him before they flirted with Bachmann and Perry.

Still, Cain stands out in the current Republican field for his charisma, plain-speaking, business experience and, yes, his color. It’s part of who he is and of his appeal to conservatives. But if Cain were white, he might very well be where he is today given the performance of the rest of the GOP field and the desire of conservatives for an alternative to Romney.