recent poll out of massachusetts after the debate shows senator brown ahead of challenger warren. that's almost a complete reversal of the numbers a week before the debate. the same poll had warren leading brown 46-44. tonight, the two senate candidates face each other. this is a third debate they have gone at it. reporter noah bearman joins me. we have seen the race go up and down. one of the most watched. you have thousands of people show up for their last debate. how do we know with any certainty that this is a down ballot impact that scott brown is seeing and maybe not the result of the debate they had? >> we don't know for sure and we don't know for sure whether the polls are temporary or signify a larger trend. she's been up in polls before this one. occasionally she's been down and come back up again. >> yeah. >> but the thing that's sort of interesting about this one is that this is hardly going to be