News media bias takes many forms and comes about for as many reasons. At times it occurs when reporters en masse are conscientiously or unconscientiously willing to be “taken in” by a prevalent brand of aggressive political spin. This type of “group buy-in” results in the press developing a sort of herd mentality about the specific issue involved.
Such a situation not only leads to one-sided and inaccurate coverage but also leads to incorrect analysis and predictions about what’s likely to take place. In addition it causes what might be called a shared blindness to evidence that would tend to contradict the news media’s consensus viewpoint.