This post will be quick but hopefully get you thinking. Consider the differences between the following two similar scenarios.
In scenario 1, Sarah Palin, a vice-presidential candidate, is being interviewed by Charlie Gibson, a member of the mainstream media. In that interview, Gibson asked Palin if she agreed with the Bush Doctrine and she asked for clarification. Gibson stared down at her over the top of his glasses with a look of contempt. The immediate reaction by the media was to say she was unqualified to be president. Of course, there are four separate definitions of the Bush Doctrine and the one Gibson picked was number three. So asking for clarification wasn't exactly out of line.
In scenario 2, Joe Biden, a vice-presidential candidate is being interviewed by Katie Couric, a member of the mainstream media. In that interview, Biden made reference to a TV speech by FDR at the start of the Great Depression and held it up as an example as how a real leader would act. Of course, there's the small problem that FDR wasn't President when the stock market crashed in 1929 and nobody really had televisions at the time. The reaction by the media? Sort of point it out but don't make a big deal about it.
Fair and balanced? You decide.