David Axelrod, senior adviser to the Obama campaign, acknowledged on Wednesday that the president's image has taken a hit due to escalating negative attack ads.  

Appearing on "Morning Joe," Axelrod responded to Tuesday's NBC News/Wall Street Journal poll, which showed that 43 percent of American voters hold a negative view of Obama — up 5 points from June's NBC/WSJ survey.  

"Understand that there have been probably $110, $120 million of negative ads run against the president in the last -- just in the last few months and so they're going to have an impact," Axelrod said. "You know, they're going to have an impact. That's just part of politics. I think what's noteworthy is the president's standing has held up under this torrent, and I think there are growing questions about Gov. Romney that he's abetted because they won't talk about his past and the future. That's a hard way to get elected president of the United States."