Democratic senator Jeanne Shaheen of New Hampshire couldn't hold back at her debate with Republican challenger Scott Brown. While Brown was giving his closing remarks at a forum in Manchester Sunday, Shaheen interrupted him, eliciting boos from GOP partisans in the crowd.

"She's voting against small business 100 percent of the time, by having a 'zero' rating from the National Federation of Independent Businesses," Brown said, adding that the group had endorsed him.

"A Koch Brothers-funded organization," said a visibly annoyed Shaheen, speaking over the Republican.

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The race between Shaheen and Brown has tightened in recent weeks, though Shaheen has held a small lead in the last five polls of the race. The Real Clear Politics average of polls gives the Democrat a 2.2-point advantage.