Respectfully Quoted: A Dictionary of Quotations. 1989.
Theodore Roosevelt (18581919)
The plea of good intentions is not one that can be allowed to have much weight in passing historical judgment upon a man whose wrong-headedness and distorted way of looking at things produced, or helped to produce, such incalculable evil; there is a wide political applicability in the remark attributed to a famous Texan, to the effect that he might, in the end, pardon a man who shot him on purpose, but that he would surely never forgive one who did so accidentally.
THEODORE ROOSEVELT, writing of John C. Calhoun, Thomas Hart Benton, chapter 5, p. 111 (1897, reprinted 1968).