I never said you can't influence anyone through propaganda. But I do not believe Americans were "brainwashed" to do anything. I think they wanted to do it.
I don't think they're brainwashed, I think they're genuinely that dumb and uneducated.
In any other civilised country, if the government started a war without congressional approval. They would riot in the streets of the capitol and stay there until they get what they want.