George Santayana
Soliloquies in England and Later Soliloquies, "Tipperary", 1922
Santayana was a philosopher who lived through the First World War and wrote bluntly about its aftermath.
the myth (Plato): It is often given as a Plato quote, including in a famous 1945 speech by General MacArthur. There is no sign of it in Plato; Santayana wrote it in 1922.
Source: Wikiquote