1. In your last prior post you said: Rosenstein was not vetted and approved as per the constitution, thus he cannot make the appointment. For one thing I don't know what relevance this has, but more importantly I don't know what "vetted and approved" means in the context of Rosenstein. He was nominated as the Deputy AG and confirmed by the U.S. Senate.
2. Levin is a smart guy and I respect him, but on this particular point I think his case is very weak.I've said before that this is not a very solid argument. Arguing the constitutionality of a DOJ appointment is specious because the U.S. Justice Department didn't even exist when the Constitution was written. It was established by an act of Congress in 1870. So there seems to be no clear constitutional basis to determine which DOJ officials require Senate confirmation and which do not.
3. Point #2 would seem to mean that for the U.S. Justice Department, the definition of "principal appointments" under the U.S. Constitution (i.e., the ones that require Senate confirmation) would have been established under the statute that created the DOJ, or under associated statutes and regulations that followed.
4. To make matters more complicated, many of the posts in the Federal bureaucracy are created through executive orders by the President, or even by cabinet secretaries. The Deputy AG position, for example, was never legislated into existence by Congress. It was created in 1950 by the sitting AG at the time. Who exactly determines which ones require Senate confirmation as "principal" appointments?