Quote: "What makes the muskrat guard his musk? Courage." Cowardly Lion in "The Wizard of Oz."
Figure of speech: hypophora (hie PAH for ah), the self-answering question.
The hypophora is useful for speeches and anti-war protests. It's also great for informal writing. But take care not to use it too much in daily conversation. ("Did you let me go to the party last weekend? No! Did you let me go to New York by myself? No!") It could get you grounded, rhetorically speaking.
Snappy Answer: "What makes the political advisor continue to give political advice? Gall!"