for example, http://en.wikipedia.org/wiki/Lincoln%E2%80%93Douglas_debates
The format for each debate was: one candidate spoke for 60 minutes, then the other candidate spoke for 90 minutes, and then the first candidate was allowed a 30-minute "rejoinder." The candidates alternated speaking first. As the incumbent, Douglas spoke first in four of the debates.
Those were 3 hour debates. Now all a politician has to do is look good holding a football.
(this is basically paraphrasing Neil Postman's work from http://en.wikipedia.org/wiki/Amusing_Ourselves_to_Death)
Amusing Ourselves to Death: Public Discourse in the Age of Show Business