As a former journalist and as a lawyer who represented newspapers for more than a decade, I can tell you that there is definitely a media bias, but it cannot easily be defined by political ideology. Certain reporters and editorial staffs definitely have their "darlings," and I cannot say how often I have seen someone favored by a paper or a reporter be protected when something runs amock in his or her career, and someone not favored be excoriated for doing the same misdeed.

Recently here in the Tampa Bay area an African American lawyer was running for the democratic nomination for a state legislator's seat. This guy has gone through several wives, had a well known addition to crack cocaine (he is allegedly clean after two rehabs) trouble with the Bar and some minor criminal history. The local paper endorsed him saying he "has learned from his mistakes." Absolute bias.

Nationally look at the free pass McCain gets on all his gaffes.
Again, abslute bias.

There is also an attitude that anyone can be taken down, anytime. Cross the media and watch how fast they'll do it.

Finally reporters have a tendency to buy into some kind of narrative and when the facts get in the way of the narrative, too often they ignore the facts. Examples...McCain is a free wheeling Maverick. He isn't. Biden is a "lunch bucket" working class guy. Not really.