12 points

This strikes me as about as good a handy proxy for the effect of press bias as you're going to get: The general "favorability" rating of the Clinton and Bush families is 12 percentage points net.

Of course the partisans can never accept this. The Democrats will say it's fair, or should be 30 points, while the Republicans will say it ought to be 12 points the other way, or 30. Needless to say, it is absurd that the contemptible Clinton's are ranked more favorably than the directionless Bush's. Needless to say, life is absurd, but absurdity is not the explanation for this difference. This is nearly entirely about the choices made by our press elite. Bush is probably suppressed a good 10 points from whatever his natural level would be, perhaps more (I don't say he deserves as high a rating as he would get, only that he would get it), and the Clinton's elevated probably 20.