I've talked to a lot of former Edwards staffers about this. Up until December of 2007, most on Edwards' staff didn't believe rumors about the affair.
But by late December, early January of last year, several people in his inner circle began to think the rumors were true.
Several of them had gotten together and devised a "doomsday" strategy of sorts.
Basically, if it looked like Edwards was going to win the Democratic Party nomination, they were going to sabotage his campaign, several former Edwards' staffers have told me.
They said they were Democrats first, and if it looked like Edwards was going to become the nominee, they were going to bring down the campaign.