- Alaska (3 votes)
- Colorado (9 votes)
- Utah (6 votes)
- New Mexico (5 votes)
- Massachusetts (10 votes)
It is mathematically possible for one of those states to go third party and bring the election to a stalemate, where nobody gets over 50% of the electoral college votes. Obviously, the odds of a stalemate increase, if more than one state goes third party.
What about the other 45 states? Well, any state where Clinton and Trump are near-even provides a good chance for a third party candidate to step in and take the lead. In that scenario, Clinton and Trump split the vote, as it were. Realistically speaking, though, that probably won't happen because Clinton and Trump are campaigning like mad in those battleground states.
Some people say it's possible that Bernie Sanders will win Vermont (3 votes) with a write-in campaign. He won my state of Oregon by a huge margin, but Oregon's "sore loser law" prevents him from winning Oregon in the general election. So there's no write-in campaign for him going on here.