Other:
A party that doesn't exist yet (and is created for an independent candidate's candidacy, like the Reform Party was) is much more likely to win a state in the next fifty years than any party that currently exists.
This.
Though there is maybe a tiny chance that some weird inter-party schism in someplace like Alaska or Vermont (didn't it briefy appear as if Murkowski might run as the Libertarian nominee?) which would result in a dissafected Republican or Democrat being forced by state election laws regarding deadlines for independent candidates to run as a Libertarian or a Green and winning in a 3 way race.