On re-reading the Hersh exerpt to refresh my memory from a couple of days ago, it appears he has two sources. One is a former Clinton administration official who claims the British government was spreading disinformation and that the Clinton administration knew about it. This person seems to be blaming the Brits for Iraq-Niger "hoax" (if it really was a hoax). The other is described both as a former intelligence officer, and as a former high-level intelligence official. In any case, "former" is a key word, and indicates that Mrs. Wilson can't be the source for Hersh's "set up" quote if she's still in the government.
What's most significant about Hersh's piece is that in March, as the controversy over the Iraq-Niger reference in the SOUA was building, a "former high-level intelligence official" stated declaratively that the insertion of that reference in the SOUA was a set up. It is no great stretch to observe that Wilson then either piggybacked his insertion into the story onto the original set up, or he continued to develop the set up. In my opinion, the latter is most likely.
What I think is possible, although we have no evidence and may never know for sure, is that Mrs. Plame-Wilson was among the (or THE) lower-level CIA analysts who OK'd use of the Iraq-Niger reference in the SOUA. WMD is supposedly her area of expertise, after all, and her husband did go to Niger for the CIA 11 months prior. Oh, the outlines of a set up are quite clear, no doubt. In my opinion, Justice is now investigating the wrong end of this saga. They should start at its genesis rather than poke around in one of its all-but-inevitable by-products, the supposed "outing" of Mrs. Plame-Wilson.