That is if people believe they have a shot. Looking at 538 Jhonson it at 0.1% and at the polls he is around 9% I think. If I show you that data would you vote for that candidate? If you are answer is no, then you are part of another well documented phenomenon called The bandwagon effect. In which people vote for candidates that are winning or have a chance at winning so they can generate utility with their vote.