President Barack Obama said Wednesday that he has seen no evidence that a scandal that led to the resignation of CIA Director David Petraeus harmed national security. “I have no evidence at this point from what I’ve seen that classified information was disclosed that in any way would have had a negative impact on our national security,” Obama said at a White House briefing. Petraeus, a decorated four-star general who received widespread praise for the surge strategy in Iraq, resigned as CIA director on Friday, citing an extramarital affair. Numerous federal government officials have told NBC News that the married...