DC (not a state obviously) is the only one I'd bet the house on. The highest Republican % *ever* was Nixon's 22% in 1972, and that was when Nixon won by 23% nationally in a less polarised era. The only way it would ever vote Republican is if that candidate were unopposed, or there was a complete switching of the party platforms.
I think every state has at least a 10% chance of voting for either party at least once in the next 50 years. That did, in fact, happen from 1964 to 1984. It's by no means guaranteed to happen again, but 50 years is a long enough time I think there's a decent chance of it.
Nope Arizona went straight GOP from 1948 to 1996
