“The first casualty when war comes is truth.”
Widely attributed to Johnson, but without any confirmed citations of original source: "The first casualty when war comes is truth," remarked Hiram Johnson, "and whenever an individual nation seeks to coerce by force of arms another, it always acts, and insists that it acts in self-defense" (Locomotive Engineers Journal, February 1929, p. 109). Arthur Ponsonby earlier said: "When war is declared, Truth is the first casualty", but the first recorded use seems to be by Philip Snowden in his introduction to Truth and the War, by E. D. Morel. London, July 1916: "'Truth,' it has been said, 'is the first casualty of war.'" Samuel Johnson expressed a similar idea: "Among the calamities of war may be jointly numbered the diminution of the love of truth, by the falsehoods which interest dictates and credulity encourages." Cf. Aeschylus#Misattributed.
Attributed