> How about a scenario in which all the people who claim to be voting for the lesser of two evils reevaluate their own defeatist attitude? If the only thing stopping a significant enough percentage of people from voting for a 3rd party is the perceived inability to win, then it's just a coordination problem.

I think that's a bit idealistic. A lot of people voted Ralph Nader in 2000, and while it's up for debate whether this cost Gore the election, I think many voters are now turned off the idea.

In a close con/dem race, I think many would rather have some of their positions represented by the resulting POTUS than shoot for the moon and risk "splitting the vote". One of the major parties would have to do some truly outrageous shit and alienate their base before this dynamic changes.