original_query: Who was Fleet Admiral William Daniel Leahy?
query: Who was Fleet Admiral William Daniel Leahy?
answer: Fleet Admiral William Daniel Leahy was a senior American naval officer who served as the highest-ranking active-duty military officer during World War II. He held various key positions, including Chief of Naval Operations, Governor of Puerto Rico, and Ambassador to France.  Most significantly, he served as Chief of Staff to Presidents Roosevelt and Truman, playing a major role in key wartime decisions.