So you posit that (a) Fitzgerald also didn't know whether Plame was or was not "covert" according to the Identies Act, and (b) if she was not, that he should have continued investigating a crime which didn't exist?
My posit above has to do with Libby's head, not Fitzgerald's head.
I've implied the questions and you haven't answered, so let me be direct:
1) Is it in your mind plausible that Fitzgerald didn't know whether Plame was or wasn't covert under the Identities Act within the first week of his investigation?
2) If Plame was not covert under the Identities Act, what was Fitzgerald's legal authority to continue his investigation?
3) Would it be ethical for Fitzgerald to have continued investigating a crime which he knew did not occur?