The People, Yes pt. 23 (1936). The popular form of this expression was crystallized when Charlotte Keyes published an article titled "Suppose They Gave a War and No One Came?" in McCall's, Oct. 1966.
Letter from the field of Waterloo in June 1815. "The Fifteen Decisive Battles of the World: From Marathon to Waterloo" by Edward Shepherd Creasy, 1851.
"The Pathway of Peace". Speech to the Canadian Bar Association, Montreal, Ontario. "The Pathway of Peace : Representative Addresses Delivered During His Term as as secretary of state (1921-1925)" by Charles Evans Hughes, September 04, 1923.
"Letters to Atticus" (1st century B.C.), as quoted in "Words on war: military quotations from ancient times to the present", book by Jay M. Shafritz, 1990.