Why Propaganda Trumps Truth

"In the simplicity of their minds, people more readily fall victims to the big lie than the small lie, since they themselves often tell small lies in little matters but would be ashamed to resort to large-scale falsehoods. It would never come into their heads to fabricate colossal untruths, and they would not believe that others could have such impudence. Even though the facts which prove this to be so may be brought clearly to their minds, they will still doubt and continue to think that there may be some other explanation." -- A. Hitler

Paul Craig Roberts elaborates here.