The terms of political discourse typically have two meanings. One is the dictionary meaning, and the other is a meaning that is useful for serving power -- the doctrinal meaning.
Take democracy. According to the common-sense meaning, a society is democratic to the extent that people can participate in a meaningful way in managing their affairs. But the doctrinal meaning of democracy is different -- it refers to a system in which decisions are made by sectors of the business community and related elites. The public are to be only "spectators of action," not "participants," as leading democratic theorists (in this case, Walter Lippmann) have explained. They are permitted to ratify the decisions of their betters and to lend their support to one or another of them, but not to interfere with matters -- like public policy -- that are none of their business.
If segments of the public depart from their apathy and begin to organize and enter the public arena, that's not democracy. Rather, it's a crisis of democracy in proper technical usage, a threat that has to be overcome in one or another way: in El Salvador, by death squads -- at home, by more subtle and indirect means.
Or take free enterprise, a term that refers, in practice, to a system of public subsidy and private profit, with massive government intervention in the economy to maintain a welfare state for the rich. In fact, in acceptable usage, just about any phrase containing the word "free" is likely to mean something like the opposite of its actual meaning.
Or take defense against aggression, a phrase that's used -- predictably -- to refer to aggression. When the US attacked South Vietnam in the early 1960s, the liberal hero Adlai Stevenson (among others) explained that we were defending South Vietnam against "internal aggression" -- that is, the aggression of South Vietnamese peasants against the US air force and a US-run mercenary army, which were driving them out of their homes and into concentration camps where they could be "protected" from the southern guerrillas. In fact, these peasants willingly supported the guerillas, while the US client regime was an empty shell, as was agreed on all sides.
So magnificently has the doctrinal system risen to its task that to this day, 30 years later, the idea that the US attacked South Vietnam is unmentionable, even unthinkable, in the mainstream. The essential issues of the war are, correspondingly, beyond any possibility of discussion now. The guardians of political correctness (the real PC) can be quite proud of an achievement that would be hard to duplicate in a well-run totalitarian state.