If Leopold's source on this is right, then it appears the a lynchpin in Fitzgerald's case against Libby is none other than Ari Fleischer, who appears to be singing like a bird.

Jason Leopold | Fitzgerald Previews Government's Case Against Libby:

" Libby told FBI investigators and testified before a grand jury that he found out about Plame Wilson's CIA employment from reporters on July 9 or 10, 2003. But Fitzgerald said Libby discussed Plame Wilson with former White House press secretary Ari Fleischer on July 7, 2003, and Fleischer testified that Libby said the information was 'hush, hush' on the 'QT' and was not widely known ..."