The dedication of a lifetime — these are words that are easy to utter, but this is a mighty assignment. For it is often easier to fight for principles than to live up to them.
Source, in full
Speech to the American Legion convention, New York City (27 August 1952); as quoted in "Democratic Candidate Adlai Stevenson Defines the Nature of Patriotism" in Lend Me Your Ears : Great Speeches In History (2004) by William Safire, p. 79 - 80