"The first casualty of war is truth"

John Pilger in a justly famous New Statesman article headed “The real first casualty of war” (24 April 2006) wrote “The oldest cliché is that truth is the first casualty of war. I disagree. Journalism is the first casualty. Not only that: it has become a weapon of war, a virulent censorship that goes unrecognised in the United States, Britain and other democracies …”
 
So if it's a cliché, who first said it?

(1) Some say Aeschylus, the Greek tragic dramatist, 525 - 456 BCE. This claim is made by several people on the internet, but none has provided a citation, and I believe the claim to be false. The Wikipedia page of Aeschylus quotes flatly denies it. Moreover a classical scholar informs me that "casualty" is a modern word, which could not be directly translated from ancient Greek.  Also "Aeschylus uses the word for truth very rarely and not that I can find in a context that would translate thus."

(2) Samuel Johnson wrote in the Idler magazine no 30, 1758.  "Among the calamities of war may be justly numbered the diminution of the love of truth, by the falsehoods which interest dictates and credulity encourages."

(3) In 1917 Hiram Johnson (1866-1945) a Progressive Party senator in California reputedly said "The first casualty, when war comes, is truth", referring to the United States entry into World War I.  However I have seen doubt cast on this, and a statement that the saying does not in fact appear in any of Johnson's recorded speeches.  If Hiram Johnson did say these words, had he read Samuel Johnson?  Hiram Johnson died on Aug. 6, 1945, the day the atomic bomb was dropped on Hiroshima. 

(4) Lord Arthur Augustus William Harry Ponsonby (1871 - 1946) was a British politician, writer, and social activist.  In Falsehood in Wartime: Propaganda Lies of the First World War (1928) he wrote "When war is declared, truth is the first casualty." 

So, interestingly, we still have not come to who first used the exact phrase "The first casualty of war is truth", or "Truth is the first casualty of war". We can imagine they had read Ponsonby, but we don't know.