Talking to Gina Cooper, I fear I may have misrepresented the way convention speakers were chosen at YearlyKos. According to her, here's how it went:
Six candidates -- Warner, Kerry, Clark, Clinton, Feingold, and Edwards were all offered lunch spots. Scheduling problems kept the non-Warner candidates from accepting/confirming. There was not a second option for a convention-wide speech; if you weren't going to do the lunch, your only option was a Friday panel. Vilsack, Richardson, and others were not proactively offered slots, but could have asked. As Gina points out, the volunteer staff was not trying to organize a primary debate, and information on the conference was publicly available for interested speakers.
There were, in my conversations, various 2008 campaigns who felt they should've been able to address the convention but there was little flexibility on the organizing side. Gina argues that this wasn't a convention for presidential candidates, and so the organizers vowed to keep it from being a presidential mixer and confine the glitz to the Saturday lunch. Current conceptions of the convention focus on the appearance of presidential aspirants, but it was really about the blogs, not the campaigns, and so the analysis is backwards. It wasn't for the convention to bend to the aspirant's schedules, but for those who wanted to address the place to work within the schedule's confines. Additionally, campaigns could hold their own events, as with the Clark and Warner parties or the Richardson breakfast.
