A new Public Policy Polling survey (June 4-6, 601 RV, MoE +/- 3.9%) finds North Carolina Sen. Richard Burr has extended his lead since last month over Democrats Elaine Marshall and Cal Cunningham. The two are two weeks away from a primary runoff contest that remains a toss up.

Burr 46 (+2 vs. last poll, May 10)
Cunningham 35 (-4)
Und 19

Burr 46 (+3)
Marshall 39 (-3)
Und 16

The results are similar to a Rasmussen survey released earlier today. While Burr holds significant leads, he's polling under 50% -- any incumbent doing so should be considered vulnerable.

Click here for more polling on the race.

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