For a black candidate in an era of dog-whistle politics, it was a gamble: tackling head on one of the trickiest subjects in America.

BBC: What's the point of presidential speeches?

In politics, a dog whistle is a rhetorical device--an oral expression susceptible to two interpretations, one straightforward and one, metaphorically speaking, at a higher frequency.

WSJ: Best of the Web Today

" As we explained last August: "In politics, a dog whistle is a rhetorical device--an oral expression susceptible to two interpretations, one straightforward and one, metaphorically speaking, at a higher frequency.

WSJ: Best of the Web Today: The Dog Whistler