Here is the statistical evidence that shows that Dean has gotten by far the most negative coverage of any of the candidates.
http://www.sfgate.com/cgi-bin/article.cgi?f=/news/archive/2004/01/15/politics2012EST0795.DTL
It is obvious that he has gotten the most coverage, but it is equally clear that it has been largely negative. This study ended in December before the incredibly vicious and negative attacks took place during the last two weeks.
I hope supporters of other candidates will not try to deny this, because I think it is inevitable that whoever the frontrunner is for the Democrats, they will be treated the same way. We must try not to play into the media's bias or we will just get another candidate "Gored" during the general election.
If you are still not convinced I would suggest looking at:
http://www.salon.com/news/feature/2004/01/13/dean_media/index_np.html