Congress and what congress does depends very much upon public opinion, and public opinion not only drives the press to some extent, but the press also drives public opinion, probably even to a greater extent in my opinion. For any president to be impeached, congress will need the media to help drive the process, to feed the fires of discontent with a politician, and to destroy his or her reputation and credibility. Of course, actual evidence is necessary in the impeachment procedure, but with enough investigators and spin, something can be dredged up, concocted, and built into something very significant. Lawyers are experts at spinning, and skewing to what they want to happen in a case. As an example of lawyers, face it, the Supreme Court supposedly is made up of the best of the lot and they can manage to invent stuff in the constitution that was never written.
I have heard said that the press is worth at least 15 points in an election. I personally think that is a conservative estimate, and of course over time, it can possibly be expanded. That is why I believe Bush was so tarnished, the press pounded on him for 8 years, and it is nothing short of miraculous that he won a second term and ended up with 30% or so approval rating after the program of spin went on as long as it did.