[Cboldt]

-- What most people may not realize is that the office of the Deputy Attorney General was never established by Congress. --

Maybe not originally established. Congress appears to have caught up, because the requirement for senate approval arises under statute, 28 USC 504 - DAG

[Alberta's Child]

Right. Note the operative term MAY in that statute. Congress simply codified the status of the Deputy AG as a post that requires Senate confirmation.

That was really a formality anyway. If the 93 U.S. Attorneys require Senate confirmation and the Deputy AG is higher in the organization than they are, then clearly the Deputy AG would be considered a "principal office" under the U.S. Constitution that requires Senate confirmation.