Berg paid for an internal poll in Q1 that he never released. Pretty telling.
I believe there've been some scandals about Berg; one poll from a questionable source doesn't prove anything, but Heitkamp could well be ahead. I wonder if there could be an upset in the primary - perennial candidate Duane Sand is running against Berg, and, while he's never been elected, I seem to recall polling that showed NoDaks had a pretty positive opinion of him. It wouldn't surprise me if Sand was actually a
stronger candidate than Berg. Perennial candidates
do break through sometimes - that's how Bernie Sanders got his start, back in the '70s.
