The big lie was something they all knew about.  How it was put together and why.

The way the big lie started off followed a reliable formula, little lies bundled up together, which to the casual observer were unconnected.  On reflection, they conjured up  strands of a hidden truth.

The big lie was cobbled together in darkness.  It played on resentments and provided a readymade enemy.

People had been hearing those big lies forever.  They never went out of style.  Doubts were as easy to stir up as a martini.

That was the thing.  All you had to do was aim it at what people wanted to believe.

You just gave them a way to believe they were superior, immune to the brainwashing that swept up the rest of the country.