There has been a concerted effort on the part of the mainstream media in the US to prevent Kucinich from getting exposure, or to shape any exposure he got in such a way as to make him look bad. They've been very effective in doing this, too. A lot of the people I encountered yesterday had never even heard of Kucinich. I was encouraged by the fact that when I told them about him and about his ideas and plans, most of them really liked what they heard.

This is why the mega-corporations don't like Kucinich (and will do whatever they can, including engaging in censorship and propaganda to keep him out of the public eye). They are afraid of him because if he is elected, he will help the voters and undermine the corporatocracy. In fact, he'll do this regardless of whether he wins or not, just by being in the race and getting exposure. If they were to allow him to participate in the debate, he would have made the other candidates and their corporatist agendas look bad, as he has done so many times before, and they know it.