The Washington Times - June 8, 2012, 12:27PM

Democrat Heidi Heitkamp has edged into a razor-thin lead over Republican Rep. Rick Berg for North Dakota’s open U.S. Senate seat, a new independent poll shows.

Results of the Mason-Dixon Polling & Research poll found Ms. Heitkamp, the former state attorney general, with 47 percent support of likely general election votes, while Mr. Berg had 46 percent. But with the margin of error at 4.5 percent, the survey shows the two essentially deadlocked.

Only 7 percent of those who responded to the poll, conducted June 4-6, were undecided on how they would vote in the November general election.

Mr. Berg, the state’s sole at-large congressman who has the support of the state’s Republican establishment, holds a 57 percentage-point lead among voters likely to participate in Tuesday’s GOP primary, the poll said.

Little independent polling has been conducted on the race. A mid-May poll by Essman/Research showed Mr. Berg with a 7 percentage-point lead over Ms. Heitkamp, though Democrats and some in the media said it was flawed because it asked likely primary voters about how they would vote in a general election.

Democrat Sen. Kent Conrad, who has held the seat since 1993, isn’t running for re-election. Both parties are desperate to win, as the Democratic caucus holds a slim 53-47 advantage in the chamber.