actually, it goes beyond the usual "company" email vs "personal" email in this case. He's an elected official. Any communications he issues using his official channels (phones, email) are public property according to Colorado law. It's the same here in Florida as well, our elected officials in the school system I work in, that is the Superintendent and School Board members, are under the same umbrella. The school board members chose NOT to have official email accounts for this very reason. The superintendent needs it, so every message he sends is CC'ed to a special archive (makes it easier on him and the email admins if they ever need to recover an email of his.)
One of our county officers here got in trouble for something he said in an email. If memory serves me correct, it was a racial comment. I can't remember if he resigned or was just reprimanded though.