Address at the Sorbonne, Paris, 23 Apr. 1910. Richard M. Nixon quoted this passage in his address to the nation announcing his decision to resign the presidency, 8 Aug. 1974. See Theodore Roosevelt 1; Theodore Roosevelt 2; Theodore Roosevelt 5
Quoted in Humphrey Carpenter, W. H. Auden (1981). Leonard L. Levinson, in Bartlett's Unfamiliar Quotations (1971), quotes this comment as being said about Auden by someone else.