The ad attempts to refute Berg's claim that he's had "absolutely no involvement" with Goldmark, and it uses audio of him saying as much. But to refute Berg's claim, it lists a myriad of evidence — including a real estate license application from Berg that notes his affiliation with Goldmark, previous reports that he was a spokesman for Goldmark and federal forms on which he listed Goldmark as an employer.

"Rick, how can we believe anything?" the narrator asks at the end.

The issue of Berg's involvement with Goldmark Property Management, which was cited for fire code violations after Berg left that wing of the company, has become a central issue in the race for North Dakota's Senate seat. Both Heitkamp and Berg are relatively well-liked, so the effort now, on the part of Democrats, remains to portray Berg as a Republican extremist out to support his own interests with his work in the real estate sector.

Republicans, alternately, are attempting to portray Heitkamp as a rubber stamp for President Obama's agenda.

The race in North Dakota is one that Republicans thought would be an easy win but have had to contend with a surprisingly strong candidate. And in a state which boasts a much stronger economy than the rest of the U.S., the race is likely to come down to small, personal issues, rather than larger issues of national policy.