Several unnamed former campaign officials said they had prepared a plan in which they would sabotage Edwards' campaign if it appeared he would secure the Democratic nomination, ABC News' George Stephanopoulos reported on Sunday.
"They were Democrats first, and if it looked like Edwards was going to become the nominee, they were going to bring down the campaign -- they were going to blow it up," Stephanopoulos said.
The strategy was apparently put together in secret in December 2007 after months of denying rumors that Edwards was having an affair with a woman and had also fathered a child with her.
The revelation comes as Edwards' ex-mistress is reportedly interested in seeking a paternity test for her 1-year-old daughter after Edwards' wife, Elizabeth, sparked fresh questions over whether the father might be her husband.
The former North Carolina senator and presidential candidate denied being the father of Frances Quinn Hunter during a TV interview in August. But Elizabeth Edwards, in an interview on "The Oprah Winfrey Show" that aired on Thursday, didn't sound so sure.
"I've seen a picture of the baby," she said. "I have no idea. It doesn't look like my children, but I don't have any idea."
On Wednesday, one day after Oprah's production company released excerpts of the interview, The National Enquirer reported that Rielle Hunter, John Edwards' former mistress, is working with a lawyer to seek a paternity test from him.
That's a reversal from last August, when Hunter's attorney Robert Gordon released a statement saying she "will not participate in DNA testing or any other invasion of her or her daughter's privacy now or in the future."
Edwards said at the time that he would "welcome" a paternity test, and that because of the "timing" of his affair "it's not possible that this child could be mine." But he indicated that his apparent willingness to take the test would lead nowhere unless Hunter consented.
"I'm only one side. I can run only one side of the test, but I'm happy to participate in one," Edwards said at the time.
It's unclear whether Edwards would be as willing to submit to a test if Hunter is on board with the idea.