> Stations that did run an editorial with a given partisan viewpoint were even required, by law, to allow an opposing view to be aired in response.
Sure, but the Overton window was quite slim. Many things were simply never discussed. Homosexuality, interracial romance, adultery of politicians, as just a few examples.
The "alternative perspective" gave the illusion of a full airing of views, but it simply wasn't so.
Early SNL (1970s) turned this into a bit on the news segment, with Chevy Chase introducing someone to respond to some (non-existent) editorial of theirs from a past program, to provide alternative viewpoints, as was their journalistic duty (which respondent invariably had mis-heard some word and so was responding, passionately, to entirely the wrong thing—that was the joke)
Stations that did run an editorial with a given partisan viewpoint were even required, by law, to allow an opposing view to be aired in response.