I'd have to guess that the prosecution's case is a slam dunk for Hall to take this tactic. I did find this interesting from his motion though. From TPM Muckraker:
Conceivably, under the Attorney General’s interpretation of his appointment power in § 546(c), an incompetent or a blatantly politically appointed U.S. Attorney could hold office like this for seven and a half years, or even longer, assuming the President is re-elected, without ever facing Senate confirmation over his or her qualifications.
Um, when did we go to eight year presidential terms?