<P> A unified combatant command (UCC) is a United States Department of Defense command that is composed of forces from at least two Military Departments and has a broad and continuing mission . These commands are established to provide effective command and control of U.S. military forces, regardless of branch of service, in peace and war . They are organized either on a geographical basis (known as "area of responsibility", AOR) or on a functional basis, such as special operations, power projection, or transport . UCCs are "joint" commands with specific badges denoting their affiliation . </P> <P> The creation and organization of the unified combatant commands is legally mandated in Title 10, U.S. Code Sections 161--168 . </P> <P> The Unified Command Plan (UCP) establishes the missions, command responsibilities, and geographic areas of responsibility of the unified combatant commands . As of May 2018, there are ten unified combatant commands . Six have regional responsibilities, and four have functional responsibilities . Each time the Unified Command Plan is updated, the organization of the combatant commands is reviewed for military efficiency and efficacy, as well as alignment with national policy . </P> <P> Each unified command is led by a combatant commander (CCDR), who is a four - star general or admiral . CCDRs exercise combatant command (COCOM), a specific type of nontransferable command authority over assigned forces, regardless of branch of service, that is vested only in the CCDRs by federal law in 10 U.S.C. § 164 . The chain of command for operational purposes (per the Goldwater--Nichols Act) goes from the President through the Secretary of Defense to the combatant commanders . </P>

What document establishes the combatant command’s mission and areas of responsibility