To do evil a human being must first of all believe that what he's doing is good... Ideology - that is what gives devildoing its long-sought justification and gives the evildoer the necessary steadfastness and determination. That is the social theory which helps to make his acts seem good instead of bad in his own and others' eyes, so that he won't hear reproaches and curses but will receive praise and honors.

Alexandr Solzhenitsyn