The concept of unified combatant commands grew out of the World War II formation of the Supreme Headquarters Allied Expeditionary Force (SHEAF), coordinating the strategy and operation of multiple service branches.
Shared administrative control also applies to direct reporting units of the Army that typically perform single or unique functions.
It is organized, manned and equipped to perform 3 roles: A theater army is responsible for the administration and support of all United States Army forces assigned, attached, under the operational control of a geographic combatant command or transitioning to that area of responsibility (AOR).
The theater army is also responsible for distribution, recovery, and redistribution of supplies and equipment in joint operations areas.
This falls under the ADCON chain of authority Responsibilities of a Service component are determined from Title 10; DODD 5101.1; DA Memo 1-10; and combatant commander’s daily operational requirements.