I do sympathize with the supportors of the third party candidates.   I worked for a year to try to open the primary ballot to all candidates and all voters, a fair way to judge public support IMO.   

But at this point neither third party candidate is a serious contender and neither would have a mandate, nor an established structure from which to generate or pass legislation.    

Go back to the primary system and build a ground floor of support.    The  hope of winning the general election with very small numbers says more about the current candidates of The Party than is does structural support for libertarians or the green party.   I'm more build from the bottom person.  

I fully support third parties candidates participation in an open primary ballot.    I would propose using Ranked Voting, or Instant Runoff to determine the final two candidates. (or accept the instant runoff winner from the open primary).

http://www.fairvote.org/rcv#rcvbenefits