Robert Mueller's appointment as Special Counsel to the Justice Department is limited to investigating Russia's involvement in the campaign of President Trump. The Special Counsel reports to the Deputy Attorney General and his authority is restricted by the order appointing him. We outlined the laws relating to an appointment of a special counsel here. The Order appointing former FBI Director Mueller restricts his authority to investigating "any links and/or coordination between the Russian government and individuals associated with the campaign of President Donald Trump," and related matters. The actual order may be viewed here.
Under federal law, a "special prosecutor" is known as a "special counsel," and is warranted in a federal criminal investigation when the Attorney General determines "(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." This law may be found at 28 C.F.R. § 600.1. In all cases, the Attorney General determines the areas to be investigated by the Special Counsel. 28 C.F.R. § 600.4. The Special Counsel is not subject to day-to-day supervision of the Department of Justice, but the Attorney General may review all activity by the Special Counsel, to determine if the Special Counsel's actions are " inappropriate or unwarranted under established Departmental practices." 28 C.F.R. § 600.7.
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