Berg's first run for statewide office was in 2010, though he did serve as a leader in the Legislature. He certainly isn't as well-known as Hoeven, who was elected in 2010 with more than 75 percent of the vote after 10 years as governor.
In Congress, Berg has been a reliable vote for the GOP majority. He announced his Senate bid just months after he was elected to the House.
Berg "has not been in statewide office long enough to really create much of an impression, in terms of being a policymaker," said Mark Jendrysik, a professor of political science at the University of North Dakota. "But he certainly says the right things to appeal to the conservative Republican base."
Heitkamp has criticized Berg's vote for the House Republicans' budget blueprint and its proposed cuts to Medicare and federal crop insurance programs. Berg defends his vote, calls the budget targets "suggestions" and implies that he will protect North Dakota's interests.
Heitkamp has also pushed her ties to the state's energy industry. Since leaving office she's served as a director at Dakota Gas, a natural gas and coal company. Like Berg, she supports hydraulic fracturing, or "fracking," the exploration technique that has led to a boom in oil production in western North Dakota.
At a recent energy-themed campaign event in Minot, she criticized Obama as dithering on Keystone, the proposed pipeline for carrying oil from Canada to Texas Gulf Coast refineries. "So we're going to wait until we have a better economy and have more costs?" she said. "You look at it now, and it makes perfect sense."
In an interview, Heitkamp made it clear she intends to keep her distance from Obama.
"I think he's failed in the one test America had for him, which was to unite the country," she told The Associated Press. "I think he needed to be more hands-on. ... I don't think he's done enough to think broadly and come up with solutions that would engage both sides in a reasonable dialogue."
Republicans say Heitkamp's tough talk on Obama is an election-year conversion and predict her past support for his health care overhaul and candidacy in 2008 will be her undoing. The latest Crossroads ad, for instance, targets her support of Obama's health care plan.
Voters, however, say they're most concerned with maintaining North Dakota's economic success.
Jay Elkin, who farms near Taylor in Stark County in southwestern North Dakota, said he's likely to vote for Berg because he "understands business, he's a successful businessman and he's been involved in government and knows his way around."
Scott Shivley, who ranches near Velva, in north-central North Dakota, came to a Heitkamp campaign event in Minot to hear more about her energy ideas. He hasn't decided whom he will support but said balancing energy development with other needs is critical.
"The energy development is toughest on people who are on fixed wages, living in towns like Minot and Williston," he said.
Jackson reported from Washington.
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