How can he still win when he loses those, and there's a decent chance he might lose them according to the polls right now. He might win states like Colorado and Virginia that used to go Republican, but that doesn't add up enough to make up for the eventual big losses. So how is he able to?
It works both ways. If it's a 50/50 election, then *both* candidates will face a challenge, and will have to thread the needle. If one or the other wins nationally by more than a couple of %age points in the popular vote, then he will inevitably win enough electoral college votes to win the election from *somewhere* (barring some really bizarre distribution of support).