With the billions spent on elections it seems only natural that certain candidates are run only "for effect". The lessons learned from Ross Perot and Ralph Nader can be applied to any party and there is plenty of money out there for games of this type.
I think the first example of this was the Ed Bradley(?) campaign in 2000. Algore was the presumptive candidate but needed some "competition" for him to run roughshod over and look good. Sort of a "political palooka" if you will. Algore was viewed as having the personality of a tree, so I'm certain Bradley was run by the party to make Algore look more lively, human and Alpha-Male like.