"It ain't what you don't know that gets you, it's the things you think you know that just ain't so."

Usually credited to Josh Billings.

It is, e.g., what turned the Iraq invasion into a national disaster. What was wasted on invading Iraq, to no purpose, could have paid, instead, for the entire transition to wind and solar, decades sooner.

Numerous billionaires minted off the fiasco would not now be actively undermining democratic institutions.