Anyone who dismisses Third Parties has forgotten recent history . Unless you've got a third party candidate with a billion dollars, you're not going to have any influence.
Perot got Clinton elected. If that's success, in your view, then you've been dropped on your head once too often.
These primary races are really showing the agenda of the borderbots on FR. If they lose they threaten to jump to a 3rd party. It will be interesting to see how long they are allowed to get away with it.