Widespread intellectual and moral docility may be convenient for leaders in the short term, but it is suicidal for nations in the long term. One of the criteria for national leadership should therefore be a talent for understanding, encouraging, and making constructive use of vigorous criticism.

-- Carl Sagan, "The Public Enemy," in Billions and Billions: Thoughts of Life and Death at the Brink of the Millenium.
New York: Ballantine Books, 1998, p. 189.