Refers to an "acquired from the past" habit/routine/action/policy, usually of questionable morals/ethics. It originates from a practice that a former U.S. prez began many years ago, and so then one or more C-in-C's have partaken of same sinfulness on numerous occasions since then because they figger that it is something they can get away with and thus they should be able to do it themselves.
A few "classic" and disgraceful examples of a precedent of the United States would be Kennedy's philandering (and so Clinton and Dubya followed suit), Nixon's dirty politics (and so Reagan did likewise, as well), and Reagan's running rough-shod over everyone (just as The Donald is doing now).
by QuacksO April 11, 2019