I would be remiss in not adding the usual caveat: While I’d rather that my candidate be ahead than behind right now, polling about November elections done in mid-June is all but worthless in predicting the outcome.

Very true, the point of a poll is an instantaneous measure of where we are now. they can do that well when conducted smartly. Figuring out "what will happen later" based on "where we are now" is a hell of a lot more complicated :)

Florida
Ohio
Pennsylvania