The thing to keep in mind about North Dakota polls is North Dakota is pretty much impossible to properly poll. That is because it DOES NOT HAVE VOTER REGISTRATION.
That difficulty of polling the electorate with any accuracy is probably one of the reasons why Heitkamp overperformed the polls in 2012.
Polling people by self identification of party is much more accurate than by actual registration anyway.
And I thought Indiana was the state with screwy poll call prohibitions.
It is not just that there is no party registration. That is the case for a lot of states.
There is literally no voter registration system at all.