[sickoflibs]

§ 600.1 Grounds for appointing a Special Counsel.
The Attorney General, or in cases in which the Attorney General is recused, the Acting Attorney General, will appoint a Special Counsel when he or she determines that criminal investigation of a person or matter is warranted and -

(a) That investigation or prosecution of that person or matter by a United States Attorney's Office or litigating Division of the Department of Justice would present a conflict of interest for the Department or other extraordinary circumstances; and

(b) That under the circumstances, it would be in the public interest to appoint an outside Special Counsel to assume responsibility for the matter.

Legal Information Institute Cornell Law School 600.1

[Meet the New Boss]

That is a regulation adopted by the Justice Department, not a law passed by Congress

It cannot trump a law requiring every US Attorney to be approved by the Senate