Here is an excerpt of John Edwards on Nightline, where the Democratic politician spent most of the time trying to explain the limited nature of his bad behavior. His affair was a brief fling he quickly told his family about, driven by "a narcissism that leads you to believe you can do whatever you want, you're invincible, and there will be no consequences." He didn't have a love child with his mistress, Rielle Hunter, and didn't know anything about any hush money she may have received. He'll take a paternity test and release the results to the news media, if someone can get Hunter to participate. And, Edwards said, he only visited Hunter again recently in a Los Angeles hotel at the insistence of a mutual friend, who promised to be present, to hear a story of Hunter's "struggles." Edwards gave the careful, plausible admission of a skilled lawyer. Whether he is believed will hinge on how people react to his most vulnerable moments. Click the video icon to watch two of them. [ABC News]