Like NeedleNose says may be the case.....
that means if Miller testifies she told Libby about Plame, Fitzgerald can't ask her where she got the information -- so if John Bolton or one of his aides (for example) told her as a way of laundering the leak, everyone could get off the hook ... unless Fitzgerald tries to prosecute Libby, Karl Rove et al. for disseminating the information after Miller passed it along to them.
But Digby gives me hope....
The question is what Fitzgerald got in return for agreeing not to ask Judy about her lovers ..er sources. And don't think he didn't get something in return.
In case anyone's wondering if Fitzgerald is really the tough guy everyone thinks he is, check out this story from last week about the Governor George Ryan trial in Illinois. You'll notice that he flipped Ryans "political son" by arresting his mistress and squeezing her until she convinced him to testify:
To read the rest
Better yet read the Avenging Liberal link pointed out in Digby's update.