I took a break from the Political Board and just happened to see this. Sorry I did not see it sooner. I was talking with Skyler Mckinley on a daily basis back in 07 and 08. He was Mike Gravel`s National Campaign Director. We would discuss this thing all of the time. Basically the media first decides who they think is a viable candidate and who is not. THEY CHOOSE who is going up for debates and who is not and they usually base that off of Fundraising totals each month or every 3 months. Sometimes, as in the case of Ron Paul and Mike Gravel, they disinvite or Don`t invite even if the money was raised. Its pretty corrupt which is why I think all debates should be done on public television. Let candidates go on Private News Stations all they want, but all Debates should be held on the public channel, be it radio, Television or the Internet.
So what it comes down to is, basically the media does in fact choose to a large degree.