Were it not for Abe Lincoln ("Four score and seven years ago . . . ") almost nobody would know that one meaning of "score" is a period of twenty years. Dating back to 1776, the USA has now been around for twelve score and five years. (Twenty score and one year ago if you prefer to start at 1619).
Not every score in that two hundred forty-five year period has lived up to the promise of the Declaration of Independence. In fact, some twenty-year periods ought to be looked at as deeply shameful times when the iron triangle of fear, tribalism, and political cowardice gripped the land. We've just lived though such a period (2001-2021), though "lived" might be an overstatement.
The years 2001-2021 will go down in history as our third score of shame, rivaled only by 1837-1857 and 1877-1897 for sheer self-induced misery. Each score saw those who fought to expand rights up against vicious attempts to abridge them. Each score in part illustrates W.B. Yeats' famous line from "The Second Coming": "The best lack all conviction, while the worst are full of passionate intensity."
In the most shameful periods of American history, public policy is dominated by the worst: bad-faith actors who exploit divisions for narrow, self-interested agendas.