This is an excerpt from a Nightline interview to be shown on Monday:
The Obama campaign accused the Clinton campaign of "fear-mongering."
"I think she has got a little desperate toward the end of this campaign," Obama told "Nightline's" Terry Moran, while campaigning in Ohio. "[She] has been a lot more aggressive in her negative attacks.
"As I've pointed out, we've actually had a pretty significant moment in the last several years, that called people's judgment into question. And that was the war in Iraq."
On the war:
Regarding the Iraq War, this weekend, Clinton told reporters that if she runs against McCain, she will "put forth my lifetime of experience. Sen. Obama will put forth a speech he made in 2002."
Obama disagrees with that characterization. "I was in the midst of a U.S. Senate race," he said. "It wasn't simply a speech. It was an ongoing opposition."
On experience:
On the question of experience, Obama welcomes the contrast between him and Clinton, who has repeatedly described herself as someone who is "tested" and "ready."
"I think the question is, how do you know any president is ready?" Obama said. "[Until] you're president, you haven't made these decisions."
"What people can take a look at is how I exercised judgment on key foreign policy questions over the last several years," he said. "And I think they can have confidence. ... More often than not, I have shown judgment that was superior to some of these people who are claiming much lengthier experience."
As part of her proven experience, Clinton has highlighted her visits to more than 80 countries, her time spent in the White House and her service on the Senate Armed Services Committee.
"Look, I've lived overseas," said Obama. "I have family overseas. I have served on the Senate Foreign Relations Committee."
As for Clinton's experience in the White House, Obama is dubious. "It is true that I've not lived in the White House," he said. "Although, one of the tough things about Sen. Clinton's campaign has been the degree to which she takes credit for good things that happened and doesn't take credit for bad things that happened."
And what about temperament:
Obama believes that his "matter of temperament" best prepares him for the White House.
"One of the things that I've known about myself for a long time," he said, "is that, in difficult or stressful moments, I don't get rattled And I don't get rattled during campaigns. I don't get rattled when things are up ... and I don't get too low when things are down."