I've been struggling with this problem for decades; the best I have been able to do is develop my ideas in this thread.Journalists do not, IMHO, so much follow leftist politicians as lead them; the rules for what makes a good story in journalism just happen to filter out conservatism and amplify leftism. Which is why journalism will always be "liberal" - and why it's so easy for "liberals" to steal a label like "liberal" and invert its meaning. Leftist politicians merely sail down the propaganda wind that journalism naturally produces.
And that is what makes McCain-Feingold so wrongheaded; CFR essentially makes "journalist" a title of nobility which entitles the owner to do what you and I are legally - unconstitutionally but "legally" - forbidden to do during the late stages of the political campaign.