Those who are supreme over every thing, whether they be One, or Few, or Many, have no longer need of the arms of reason; they can make their mere will prevail; and those who can not be resisted are usually far too well satisfied with their own opinions to be willing to change them, or listen without impatience to any one who tells them that they are in the wrong.
 John Stuart Mill, Considerations on Representative Government (1861). copy citation

Context

“That this most desirable effect really attends the admission of the less educated classes to some, and even to a large share of power, I admit, and have already strenuously maintained. But theory and experience alike prove that a counter current sets in when they are made the possessors of all power. Those who are supreme over every thing, whether they be One, or Few, or Many, have no longer need of the arms of reason; they can make their mere will prevail; and those who can not be resisted are usually far too well satisfied with their own opinions to be willing to change them, or listen without impatience to any one who tells them that they are in the wrong. The position which gives the strongest stimulus to the growth of intelligence is that of rising into power, not that of having achieved it; and of all resting-points, temporary or permanent, in the way to ascendancy, the one which develops the best and highest qualities is the position of those who are strong enough to make reason prevail, but not strong enough to prevail against reason.” source