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Army Service Component Command
Responsibilities and Organization

This appendix focuses on the functions, responsibilities, and capabilities of those operational-level organizations formerly known as echelons above corps. It addresses the dynamic nature of the theater strategic and operational requirements in the states of peacetime, conflict, and war. It contains requirements for establishing and designing a theater. It describes responsibilities, functions, and organizations required to conduct major operations and provide logistical support. It pinpoints the functional, operational, and support responsibilities of the Army service component commander (formerly known as the theater army commander) in the theater.

The Army service component serves as the senior Army echelon in a theater and is the Army service component command of a unified command. It includes the service component commander and all Army personnel, organizations, units, and installations that have been assigned to the unified command. The Army's operational-level organizations assist and augment tactical (corps and division) organizations.


During periods of peacetime deployments and training where Army forces pass through the area or operate within a CINC's AOR, but are not assigned to that CINC, the ASCC coordinates with the ASCC of the appropriate CINC to ensure those forces are supported. However, except as the NCA directs, all forces operating within the geographic area assigned to a combatant command shall be assigned or attached to and under the command of that combatant commander. The architecture of the Army in a theater is flexible enough to meet the needs of combatant commanders. The ASCC has a number of capabilities and options for organization and provides the capabilities that support a force-projection concept--from an austere to a fully developed theater.

The total capabilities the ASCC provides may not be initially required in theater for the early stages of a force-projection operation. Rather, the ASCC structure represents capabilities that would be task-organized into a selected force based upon the mission, assessment of the operational environment, constraints, restraints, and the commander's risk assessment. Each theater is unique. The functional requirements of a theater organization remain somewhat constant. The variable is the level of capability required. The ASCC tailors units to provide the specific capabilities the CINC requires and echelons those capabilities as required into the theater.


Historically, echelons of command at the operational level of war (EAC) have gone through an evolutionary process. During the Civil War, the Army began evolving toward larger, Army-level units with a single commander directing large forces dispersed in multiple locations. Then, during World War I, the theater commander used an intermediate headquarters--the field army--to control multiple corps. The World War II structure expanded this, using army groups and field armies between the theater and corps commanders. These Army groups were formed to control two to five field armies. In turn, the field army could control a like number of corps. Essentially, an army group could control a maximum of 25 corps.

With the structuring of the Army around a four-corps base, the requirement for the army group and field army was eliminated. However, the functions performed by the army group and field army were not eliminated, resulting in those functions (Title 10) being performed by a forward-deployed theater army and its requisite subordinate organizations performing specific functions. Additionally, the requirement for a multiple corps operation required the capability to constitute at least an operational-level headquarters (a numbered army) for C² of the operations.

Should multinational forces be added to a conflict, as we anticipate to be the case, larger formations are possible. The issue then becomes one of span of control for the theater CINC. Modern forces have a significant mobility advantage over their World War II counterparts, where the US Army last formed army groups. That mobility advantage permits smaller formations to operate over larger AOs. Army echelons reflect the unified command structure, increased span of control capabilities, and improved weapons technology. Corps serve as the Army centerpiece for structure and are normally the building blocks upon which the Army organizes. The ASCC, formerly called the theater army commander, carries out the Title 10 responsibilities within the theater.

Subordinate JFCs may control multiple US Army corps without an intermediate Army headquarters. Then, the ASCC carries out the Title l0 responsibilities in lieu of the theater army. However, the ASCC may choose to organize a numbered army as an intermediate headquarters between the corps and the JFC to command and control operations when required by METT-T. Army organizations are structured to enable them to perform the missions to which they are assigned. At corps and below, those missions are primarily tactical. Corps and below units must be augmented to perform at the operational level. Still, units that normally operate at the tactical level may not have the operational perspective necessary to skillfully link tactical operations to strategic objectives.

When a corps or division is fully engaged at the tactical level, it cannot be expected to assume responsibility for the additional functions and command responsibilities that correspond to the operational level. It has neither the personnel nor materiel resources to perform both responsibilities. Chapter 6 discusses these additional requirements in detail. Under the force-projection concept, a tactical-level unit may conduct operational level operations. In principle, these operations should be performed by an echelon not directly responsible for commanding tactical operations. The tactical force commander must be free to concentrate resources on the tactical mission. Whereas, the operational-level commander must be free to concentrate resources on the performance of the three operational-level tasks--joint, multinational, and interagency linkage; conduct of Army operations; and support of Army operations.

The Army contributes operational-level organizations to support joint and multinational operations. Operational-level units fight and support, as well as make up a support base. Operational-level forces may be part of a forward presence that serves as a symbol of US national resolve. Other forces remain in the US to provide rapid force projection to forward-deployed units or to execute contingency operations. Whatever the case, Army leaders need to be familiar with those Army operational-level forces that contribute capabilities to joint and multinational operations. US Army levels of command include--

  • Army service component command.

  • Numbered army.

  • Corps.

  • Division.

  • Brigade, regiment, or group.

  • Battalion or squadron.

  • Company, battery, or troop.

These echelons of command provide a means for commanders to achieve operational- and tactical-level objectives. Each of these echelons has its own set of capabilities and considerations.


The Chief of Staff of the Army, with the CJCS and unified command authorities, configures the Army service component to the unified commands to meet theater requirements.


In peacetime, the CINC normally exercises COCOM through the ASCC. The ASCC must have a strategic and operational perspective while executing his responsibilities. He serves as the principal advisor to the CINC for supporting and employing ARFOR in theater. The ASCC participates in mid-and long-range planning to support the CINC's theater strategy and campaign plan, conducts major operations that support the CINC's campaign plan, and provides sustainment and support of all ARFOR assigned or attached to the theater. The ASCC may exercise OPCON of selected forces. He may command forces executing combat operations or MOOTW.

The ASCC performs three strategic and operational-level tasks--

  • Establish linkages and coordinate with the joint force headquarters and other service component commanders.

  • Conduct operations.

  • Conduct support operations to sustain the ARFOR assigned to the theater.

The ASCC's strategic task in peacetime is to carry out the strategic logistics tasks and priorities for the CINC. The ASCC's operational role in peacetime is to plan and conduct operations and exercises to execute the CINC's theater strategy and plans. The ASCC is responsible for sustaining all forces in theater and maintaining the capability to expand to accommodate ARFOR required for theater operations plans. For a complete discussion of service component responsibilities, see Joint Pub 0-2, Chapter 3.


As the theater transitions to conflict or war, the CINC may choose one of several options to exercise COCOM. Each of these options has different impacts on the employment of ARFOR. The CINC may choose to continue to exercise COCOM through the ASCC. The ASCC would conduct major operations and continue to provide sustainment and support of all ARFOR assigned or attached to the theater. The CINC may assign the ASCC support-related tasks solely or a combination of both support and operational tasks.

The CINC may choose to exercise COCOM through a JTF for a limited duration mission. The ASCC would place ARFOR under OPCON of the CJTF for the conduct of operations. The CINC also could designate the ASCC as the CJTF. The ASCC would focus on all three operational-level tasks. The CJTF may choose to organize his command by service element, functional component, subordinate JTF, or any combination of these. The ASCC, if not the CJTF, would continue to focus on sustainment and support of all ARFOR assigned or attached to the theater.

The CINC may choose to exercise COCOM directly over specific forces. The ASCC would place ARFOR under the direct OPCON of the CINC for the conduct of operations. The ASCC would continue to focus on sustainment and support of all ARFOR assigned or attached to the theater. If the CINC chooses to exercise COCOM through functional component commanders, three scenarios are possible.

  • The functional component commander might also be the ASCC. The ASCC would conduct major combat operations and support operations for the theater.

  • The functional component commander might also be an Army commander--but not the ASCC. In this scenario, the ASCC could establish a numbered army, and the numbered army commander could be the functional component commander. The ASCC would place ARFOR under OPCON of the numbered army commander for the conduct of operations. Within the functional organization, the numbered army commander would perform the three operational-level tasks. However, the ASCC would continue to focus on sustainment and support of all ARFOR assigned or attached to the theater.

  • The functional component commander might also be a commander from another service such as the Marine Corps. In this scenario, the ASCC would place ARFOR under OPCON of the functional component commander for the conduct of operations. Within the functional organization, the ARFOR commander would perform the three operational-level tasks. The ASCC would continue to focus on sustainment and support of all ARFOR assigned or attached to the theater.

As the theater transitions to conflict or war, the probability increases that the CINC will separate the ASCC's operational responsibilities from its support role. The CINC may designate another commander to focus on conducting combat operations, while the ASCC concentrates on conducting support operations.


The ASCC provides to the CINC a collection of capabilities, functions, and C² elements to accomplish the mission. With the initial deployment of forces, the ASCC, based on METT-T, tailors his organization to provide the required support to conduct major operations, battles, and engagements. The ASCC's support function has a major impact on the design and conduct of campaigns and major operations. The ASCC must get the right ARFOR to the right place at the right time to enable the CINC to strategically concentrate forces and logistics to generate decisive combat power. Figure A-1 illustrates the capabilities and functions the ASCC provides.

The ASCC becomes intimately involved with decisions concerning competing demands for limited resources. He assists the theater CINC in the development of support priorities, particularly those affecting other services. To support the force-projection concept and in addition to projecting forces and support, the ASCC must also coordinate the projection of additional required support from CONUS, another theater, or an intermediate support base, using air lines of communication (ALOCs) and sea lines of communication (SLOCs). Figure A-2 illustrates this situation.

In contingency operations, upon entry into the AO, US forces may be either opposed or unopposed. Each type entails a different mix of forces and capabilities. The existence of little or no in-theater support base may require that a large logistics organization, with augmentation from strategic and operational-level logistics organizations, accompany the deploying tactical unit. The synchronization of the deployment of CSS units, supplies, and C² with the increase in combat capabilities is critical.

Theater logistics support requires a seamless logistics profile, from strategic logistics--DLA, USAMC, and General Services Administration--to logistics field units. The historical C² and support structure provided in a mature theater may not be in place. Units must rely on a logistics system that operates on the basis of projecting and supporting force capability instead of supporting units and echelons. Implementation of concepts, such as split-based operations, total asset visibility, in-transit visibility, real-time communications, and pre-positioned materiel (on land and afloat), along with improved strategic lift capability, ensures sustainment of the projected force. FM 100-16 describes these concepts in detail.

Because of the changing nature of the force size, necessary time frame, and resource constraints, units must be capable of providing mission-essential support before the arrival of doctrinal logistics units or when deployment of logistics units would exceed what is required to support the force's mission. Mission- and capability-oriented modular elements are designed to support combat-essential requirements through sequencing capabilities into the AO. The capability projection of logistics support must focus on two critical areas: essential requirements and the strategic end state. Decisions made early in the process affect the end result. If a developed support infrastructure is absent or eliminated in an area, an ASCC headquarters could serve as the nucleus for a theater base development process. One example of a possible ASCC headquarters organization is shown in Figure A-3. For other examples refer to FM 101-5.

The ASCC headquarters conducts planning and coordinates major operations and support through flexible combinations of area and functionally oriented organizations. Headquarters management involves managing the organization and administration of the headquarters, including--

  • Coordinating and supervising movement, internal arrangement, space allocation, and administrative support.

  • Supervising agencies that service the command, such as the American Red Cross; civilian safety personnel; morale, welfare, and recreation personnel.

  • Recommending manpower allocation, especially in the use of personnel authorized in large numbers to the headquarters.

  • Allocating shelter in the headquarters area for troops, in coordination with the G3 for area organizations and the G4 for provision of shelter.

  • Providing control and standardization of procedures within the headquarters. All staff officers are responsible for proper administrative activities within their own staff sections.

The ASCC is responsible for managing the Army's support base in a developed theater. Besides managing the Army's support base, the unified commander may designate the ASCC as the JRAC responsible for surface security of the entire JRA, organization and operation of the theater support base, and conduct of rear operations for all land component services (Joint Pub 3-10.1).


A developed theater consists of forward-deployed resources and forces with some level of installation and HNS. In war, this theater support base, or JRAC, would be located in the intratheater COMMZ or in a dispersal area. The ASCC operates within the theater's developed infrastructure and ClNC's strategic priorities to receive forces and resources through seaports of debarkation (SPOD) and aerial ports of debarkation (APOD). The ASCC establishes the logistics infrastructure for the theater of operations and assists in establishing and adjusting theater LOCs. The ASCC receives, equips, marshals, stages, and moves units forward to the tactical assembly areas for employment. The ASCC continues to support and reconstitute these deployed ARFOR. Upon termination of conflict, the ASCC continues to provide support to the ARFOR to allow redeployment and reconstitution of the force. The theater organization with a COMMZ is depicted in Figure A-4.

Multifunctional Logistics Support

The CINC, with advice from the ASCC, may organize logistical support in his AOR with single, subordinate commanders responsible for large geographic areas. Normally, the ASCC places these areas under the command of a logistics C² headquarters. The ASCC may further divide the support areas into smaller areas assigned to a logistics task-organized support element. The ASCC establishes as many logistics headquarters and logistics task organization elements as needed to efficiently support his force in theater. Figure A-5 illustrates this area command structure.

Logistics Command and Control Headquarters

The ASCC must provide total support to all ARFOR in theater. If the ASCC chooses to focus on operations and streamline his span of C², he may establish a deputy commander for support and make him responsible for oversight of the total support mission. Or, he may choose to retain control of the support function and orchestrate it through his deputy chief of staff for support or appropriate coordinating staff office--that is, DCSPER, deputy chief of staff for logistics (DCSLOG), or deputy chief of staff for resource management (DCSRM).

To orchestrate the many supply and service missions, the ASCC establishes a logistics C² headquarters in the COMMZ. It provides reception and operation staging to units located in or passing through the COMMZ. This reception and operation staging includes personnel and administration support, direct support (DS) maintenance, and supply, field services, and local transportation provision.

The logistics C² headquarters provides backup logistical support to corps or other subordinate units and performs general support (GS) maintenance to support the Joint Theater Logistics System (JTLS) under work load direction of its materiel management center (MMC). The logistics headquarters coordinates area functions, such as traffic circulation and population control, with host nation agencies and MPs and coordinates property maintenance activities with the engineers. This headquarters provides an organization for centralized control of all Army EOD efforts in the theater. This provision allows the ordnance organization commander, with direction from the ASCC's staff, to quickly focus EOD assets to critical locations or operations. FM 9-15 covers EOD structure and operations.


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