The BBC kind of does that commitment, doesn't it? As do many other public service channels, like NPR. See also http://ethics.npr.org/
Of course it can be discussed what the political leanings of the outcomes actually are.
Of course it can be discussed what the political leanings of the outcomes actually are.
To put it another way: it's very possible to interpret fairness and impartiality in creative ways. And some NPR member stations make a habit of this.
Pre David Kelly they used to take their commitment more seriously.