The propositions argument is not only a logical fallacy, but also discourages democracy.  It is illogical to argue that because Ralph Nader got a few votes in New Hampshire and Florida that if he was not on ballot they would have voted for Al Gore instead.  Furthermore, the American electoral framework is comprised almost exclusively of a two party system, and any candidate who runs on a third party ballot needs to be given extra support just to have any chance at all of even securing just a few votes.