There is an expression that goes like this, "Those who fail to remember the past are doomed to repeat it." The converse is usually assumed to be true, that is, that those who know the past can prevent the worst elements from manifesting themselves again.
Here is a quote from the past that I find relevant to contemporary American affairs:
The American fascists are most easily recognized by their deliberate perversion of truth and fact. Their newspapers and propaganda carefully cultivate every fissure of disunity, every crack in the common front against fascism... They claim to be super-patriots, but they would destroy every liberty guaranteed by the Constitution. They demand free enterprise, but are the spokesmen for monopoly and vested interest. Their final objective toward which all their deceit is directed is to capture political power so that, using the power of the state and the power of the market simultaneously, they may keep the common man in eternal subjection."
Henry A. Wallace, 1944