Journalists commonly divide information from persuasion, as when they separate the “news” from the “opinion” section, or “reporters” from “columnists.” This is fine as far as it goes (and they get criticized harshly when they don’t honor this norm), but the distinction won’t help much in understanding why the 2016 campaign has been such an intellectual challenge for the media.
Everything that happens in election coverage is premised on a kind of opinion: that our votes should be based on reliable information about what the candidates intend to do if elected. Remove that assumption and the edifice crashes. But this is exactly what the candidacy of Donald Trump does. It upends the assumptions required for the traditional forms of campaign journalism even to make sense.