text: Corps Roles, Functions, and Organizations
  JOINT TASK FORCE HEADQUARTERS
  4-10. The corps headquarters is the preferred Army unit to use as the core element for forming a JTF
  headquarters for limited contingency and crisis response operations. This is accomplished by adding
  augmentation from other Services and special operations personnel to transform it into a JTF headquarters.
  This augmentation includes officers inserted into the functional and integrating staff cells, and additional
  personal staff sections. This augmentation does not include the personnel needed to augment the corps
  headquarters battalion network capability.
  4-11. A corps headquarters designated as a JTF headquarters requires a separate ARFOR headquarters
  because of the differing roles and responsibilities inherent in each. For example, JTF’s focus on the
  operational level of war and use joint rather than Army doctrine. The joint task force commander normally
  exercises OPCON over most forces and other resources in the joint operations area. A JTF can include
  functional and Service components. In addition to U.S. forces, JTFs often contain multinational forces from
  allied and coalition partners, such as in Combined Joint Task Force—OPERATION Inherent Rresolve.
  JOINT FORCE LAND COMPONENT COMMAND HEADQUARTERS
  4-12. The corps headquarters is the preferred headquarters to form the nucleus of a joint force land
  component command in limited contingency operations. The corps headquarters can command joint land
  forces with augmentation from the Marine Corps and other unified action partners. It has the necessary staff
  and experience to control land operations across a JOA. When a mission dictates, the corps headquarters
  identifies and fills needs for specialized skills not organic to the corps headquarters. The headquarters
  organizes according to the joint force commander’s (JFC’s) implementing directive. This document
  establishes the roles and responsibilities of the joint force land component, assigns the mission, and
  designates forces. Normally, the joint force land component staff consists of corps staffs augmented with
  members of the other Service components. The distribution of other Service personnel onto the corps staff
  allocates key staff billets so that all Services share equitably in staffing tasks. Ideally, the deputy joint force
  land component commander or chief of staff comes from a different Service. Replicating this construct
  throughout the staff leadership ensures all leaders understand the distinct capabilities of each Service to
  optimize employment of the forces. The corps commander as the joint force land component commander
  provides the core elements of the staff to assist in planning, coordinating, and executing functional land
  component operations.
  4-13. When designated as a joint force land component command, the corps exercises TACON or OPCON
  over Marine Corps forces, as required by the JFC, in addition to its attached Army forces. A corps functions
  as an operational-level headquarters. A corps is likely to become the joint force land component command
  when the Army provides most of the land forces. Land operations achieve campaign objectives directly
  through land operations or indirectly through supporting other components of the joint force.
  4-14. Joint land operations require synchronization and integration of all instruments of national power to
  achieve strategic and operational objectives. Normally, joint land operations also involve multinational land
  forces. Joint land operations include control of an assigned AO. The joint force land component command
  employs land forces, supported by naval and air forces (as appropriate), to achieve military objectives in vital
  areas of the operational area. The corps serving as the ARFOR assumes the additional administrative
  responsibilities over all Army forces in the operational area. As required by the JFC, a corps normally
  receives a special operations liaison element and supports special operations forces throughout the land AO.
  4-15. When designated as a joint force land component command, the corps follows joint doctrine. As a joint
  force land component headquarters, the corps has tasks that include, but are not limited to—
  * Coordinating the planning and execution of joint land operations with the other components and
  supporting agencies.
  * Designating the target priorities, effects, and timing for joint land operations.
  * Providing mutual support to other components by conducting operations in the JOA.
  * Coordinating with other functional and Service components in support of achieving the JFC’s
  objectives.