Washington( CNN) In announcing the appointment of a special counseling to oversee the investigation of Russian governmentefforts to influence the presidential election, Deputy Attorney General Rod Rosenstein said he made the move in part because of the “unique circumstances of this matter.”

By choosing former FBI Director Robert Mueller to serve, Rosenstein picked an FBI veteran with broad support on both sides of the aisle and sterling reputation. The move takes Justice Department leadership out of the equation and clears the style for Mueller to have the resources to conduct the investigation.

The code of federal regulations provides that the attorney general will appoint a special counseling when the attorney general “determines that criminal investigation is warranted and that an investigation by the Justice Department would present a conflict of interest ‘or other extraordinary circumstance’ and that ‘under the circumstances it would be in the public interest to appoint an outside special counsel.”