Moreover, section 7803(a) explicitly provides that there shall be a Commissioner of Internal Revenue who shall administer and supervise the execution and application of the internal revenue laws.Relevant Case Law:United States v. Fern, 696 F.2d 1269, 1273 (11th Cir. 1983) - the court declared [c]learly, the Internal Revenue Service is a 'department or agency' of the United States.Salman v. Dept.