Katie Couric asked each candidate why they think so many prominent political figures risk so much with marital infidelity.
Obama said in part:
I have no idea. The more I'm in public I don't even want to pick my nose... I'll leave that to the psychologists... I want to make sure that people, that, that there is no gap between who I am and the face that I'm presenting in the world. You want people to know that what you say is what you mean.
McCain hedged and wouldn't address the question, so Couric followed up a second time. He said in part:
"I don't know and I don't understand people's personal lives... I'm really not running to president to address [that]... I really don't make any comments about that... I want to be a good president and try to lead an honorable life... I've been an imperfect servant so I'm not judging."
WATCH THEIR FULL ANSWERS: