Claim: Colin Powell served in a body of the United States Department of Defense.

The Chairman of the Joint Chiefs of Staff -LRB- CJCS -RRB- is , by U.S. law , the highest-ranking and senior-most military officer in the United States Armed Forces and is the principal military advisor to the President , the National Security Council , the Homeland Security Council , and the Secretary of Defense . While the Chairman of the Joint Chiefs of Staff outranks all other commissioned officers , he is prohibited by law from having operational command authority over the armed forces ; however , the Chairman does assist the President and the Secretary of Defense in exercising their command functions .   The Chairman convenes the meetings and coordinates the efforts of the Joint Chiefs of Staff -LRB- JCS -RRB- , an advisory body within the Department of Defense comprising the Chairman , the Vice Chairman of the Joint Chiefs of Staff , the Chief of Staff of the Army , the Chief of Naval Operations , the Chief of Staff of the Air Force , the Commandant of the Marine Corps , and the Chief of the National Guard Bureau . The post of a statutory and permanent Joint Chiefs of Staff chair was created by the 1949 amendments to the National Security Act of 1947 . The 1986 Goldwater-Nichols Act elevated the Chairman from the first among equals to becoming the `` principal military advisor '' to the President and Secretary of Defense .   The Joint Staff , managed by the Director of the Joint Staff and consisting of military personnel from all the services , assists the Chairman in fulfilling his duties to the President and Secretary of Defense , and functions as a conduit and collector of information between the Chairman and the combatant commanders . The National Military Command Center -LRB- NMCC -RRB- is part of the Joint Staff operations directorate -LRB- J-3 -RRB- .   Although the office of Chairman of the Joint Chiefs of Staff is considered very important and highly prestigious , neither the Chairman , the Vice Chairman , nor the Joint Chiefs of Staff as a body has any command authority over combatant forces . The Goldwater-Nichols Act places the chain of command from the President to the Secretary of Defense directly to the commanders of the Unified Combatant Commands . However the services chiefs do have authority over personnel assignments and oversight over resources and personnel allocated to the combatant commands within their respective services -LRB- derived from the service secretaries -RRB- .   The Chairman may also transmit communications to the combatant commanders from the President and Secretary of Defense as well as allocate additional funding to the combatant commanders if necessary . He also performs all other functions prescribed under or allocates those duties and responsibilities to other officers in the joint staff under his name .