Because, really, by May everybody figured that Edwards was done.
How so very… dramatic:
…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.
See also The Daily Beast. I don’t know what’s funnier: that they had a ‘doomsday strategy’, or that there was actually anybody left by January 2008 that honestly thought that Edwards had a shot at winning the Democratic nomination. Besides, why go through anything convoluted? If they really wanted to torpedo their candidate thoroughly, all they had to do was rehire Amanda Marcotte.