On November 14, 1957, President Dwight D. Eisenhower told a defense conference: “Plans are worthless, but planning is everything.” He said he had heard it “long ago in the Army.” His reason: “the very definition of ’emergency’ is that it is unexpected, therefore it is not going to happen the way you are planning.”
Another version, “Plans are useless, but planning is indispensable,” appears in Richard Nixon’s book Six Crises (1962). Nixon was paraphrasing Eisenhower.