Heitkamp. There wasn't an "other" candidate in this race
Well, there was if you count the trainwreck write-in campaign of Independent Bill Kiefer, but he didn't even break 1% and he reportedly neglected, killed and was charged with the deaths of nearly 100 of his own horses. So all 3 candidates in this race were terrible in their own right which is why I would have just written in outgoing Senator Kent Conrad's name.
Why not just vote Heitkamp?
Muh gun control
You can't be elected without the NRA backing in North Dakota.