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.
Aldous Huxley (1937). “Ends and Means: An Inquiry Into the Nature of Ideals and Into the Methods Employed for Their Realization”, p.71, Transaction Publishers