"I remember during one Roosevelt Room prep session before I appeared on the Sunday shows, I objected when Dan Pfeiffer wanted me to say Social Security didn't contribute to the deficit," Geithner wrote in his new memoir, "Stress Test: Reflections on Financial Crises." "It wasn't a main driver of our future deficits, but it did contribute. Pfeiffer said the line was a 'dog whistle' to the left, a phrase I had never heard before. He had to explain that the phrase was code to the Democratic base, signaling that we intended to protect Social Security."