LePage can only win in elections with three candidates, and I doubt this will be a three-way election.
The Democratic party will just skip out on that Maine Senate seat? I don't think so.
If there's a Democratic-leaning and Democratic-caucusing independent already there, and a threat of Paul LePage taking the seat, yes.
If they're smart enough, yes. However, history has shown that whenever there is a powerful independent in a Maine race, its almost always a 3-4 person race. Just look at all the gubernatorial races from 1990 onward. Unlike Sanders, I don't think King is exclusively left wing, so the Democrats could still run someone.
You'd sound more believable if you don't remember 2012, where Democrats straight up abandoned the race in King's favor. There's no way in hell the Democrats put someone up against King besides some local nobody who registers against the parties wishes, and there's no way in hell a corrupt moron like Paul LePage wins a two way race against King.