Thing is objectivity can't be reached and Lehrer's says it : the only thing yyou can do is try and be fair. It's a big misconception that medias were objective before. Newspapers have always had political leanings (clear and revendicated as the identity of the magazine) and that just never stopped. To say a media isn't objective with their political coverage is actually the norm and what should be expected. Now if a media trumps a fact in favor of an argument in a paper that explain science, that's wrong. But actually I don't think any media does that (never on purpose. And mistakes usually are corrected).