10 U.S.C. § 163 — Role of Chairman of Joint Chiefs of Staff

(a) Communications Through Chairman of JCS; Assignment of Duties Subject to the limits in section 152(c) of this title, the President may: (1) direct that communications between the President or the Secretary of Defense and the commanders of the unified and specified combatant commands go through the Chairman of the Joint Chiefs of Staff; and (2) give the Chairman duties to help the President and the Secretary of Defense carry out their command role. (b) Oversight by Chairman of Joint Chiefs of Staff (1) The Secretary of Defense may give the Chairman of the Joint Chiefs of Staff the job of overseeing the combatant commands' activities. This assignment does not give the Chairman any command authority. It also does not change the combatant commanders' own responsibilities, as section 164(b)(2) of this title sets them out. (2) Under the Secretary of Defense's authority, direction, and control, the Chairman acts as spokesman for the combatant commanders — especially about what their commands operationally need. In this role, the Chairman must: (A) talk with the combatant commanders and get information about their commands' needs; (B) evaluate and combine that information; (C) advise and recommend to the Secretary of Defense about what the combatant commands need, both individually and together; and (D) pass along the combatant commands' needs to other parts of the Department of Defense, as appropriate.