text: Chapter 3
  resumes daily operations posture. The environment of the theater of operations returns to competition, and
  the theater army will continue to consolidate the gains made by adapting its activities accordingly.
  THEATER ARMY LIMITATIONS
  3-118. The limitations of the theater army headquarters are—
  * The theater army is not designed, organized, or equipped to function as a JTF, JFLCC, or a field
  army in large-scale combat operations without significant augmentation.
  * The main command post operates from a fixed location and is not mobile.
  * The main command post can provide personnel for a multinational land component headquarters,
  but this degrades the ability of the headquarters to provide and control theater-level support across
  an AOR.
  * The contingency command post requires joint augmentation for employment as a JTF
  headquarters. With augmentation, it can become a JTF for limited contingency operations.
  * Although the contingency command post is deployable, it has limited endurance without
  reinforcement and additional security.
  * Augmentation for both a JTF and for theater-level capabilities is frequently provided by forces
  mobilized from the United States Army Reserve and Army National Guard. These forces must be
  mobilized and deployed from the continental United States and require potentially lengthy
  mobilization timelines.
  SECTION II – FIELD ARMY
  The functions of an Army are: (1) to defeat the enemy’s main force; (2) seize upon his
  vitals.
  Sir Ian Hamilton
  3-119. As a provisional Army headquarters, a field army does not have an approved organizational design.
  However, the field army may consist of a headquarters battalion with subordinate companies, and special
  troops; a variable number of attached corps; an attached ESC; a variable number of divisions normally
  attached to corps; and other attached functional and multifunctional brigades.
  3-120. The field army is an operational headquarters. During operations, forces will be assigned or attached
  to the field army. Although it may employ subordinate units during operations, these units are provided by
  external Army, joint, and multinational sources based on the situation, and the field army’s role and mission.
  When constituted, a field army is specifically tailored to mission requirements and designed to perform
  operational ARFOR tasks; it is the Army component to the JFC to which it is assigned.
  3-121. The field army provides additional operational capacity to a GCC facing peer adversaries in its AOR.
  The field army can conduct land-based activities in competition against that adversary on behalf of the GCC
  and, due to its presence, is postured to transition to a warfighting headquarters capable of immediately
  commanding and controlling large-scale combat operations should conflict occur. The field army is tailored
  based on the capabilities of the peer adversary. As the adversary’s capabilities change, so do those of the
  field army.