During the 1950s, Isaiah Berlin wrote a famous essay entitled “The Hedgehog and the Fox.” The point behind the title is that the hedgehog knows one big thing and the fox knows many things. From this distinction, Berlin suggests there are two intellectual types: one who relates everything to a single idea and the other who explores a diversity of ideas. It is difficult and unrealistic to pigeonhole Fisher as one or the other intellectual type. The reality is that Fisher combines both types. My sense is that Fisher's wide diversity of scholarly and policy-influencing accomplishments, and his skepticism of conventional wisdom, put him in Berlin's second category rather than first. However, my position at the Congressional Research Service (CRS) also prompts me to say, on the other hand, one big idea has animated Fisher's contributions to the academic and political/legislative worlds. That idea is highlighted in the title of one of his plethora of publications: Defending Congress and the Constitution (2011). Of course, when you write about the Congress and the Constitution, you analyze—like Berlin's fox—a host of interrelated ideas and relationships: history, law, the presidency, the judiciary, and more.