text: Armies
  3-108. Concurrently with actions intended to confront and deter an adversary, the theater army commander
  sets the theater to enable landpower to exert its full capabilities. Enabling landpower may include negotiating
  and contracting through the GCC with adjacent nations to establish tactical staging bases and realignment of
  security cooperation efforts based on emerging threats.
  3-109. The theater army requests not only forces involved in deterrence, but also the theater-level units
  necessary as the deterrence requirements expand or to support operations if deterrence fails. An important
  consideration for the theater army is training for Army forces deployed as a deterrent option.
  THEATER ARMY IN CONFLICT
  3-110. When the GCC determines deterrence is not working and a situation is moving from competition to
  conflict, the GCC seeks to seize the initiative. Once authorized, this involves both defensive and offensive
  operations at the earliest possible time. This forces the enemy to react and sets the conditions for decisive
  operations on favorable terms. When the GCC determines that joint combat power is sufficient to seize the
  initiative, then the theater army’s priority shifts to setting, sustaining and protecting deployed forces in the
  joint operations area.
  3-111. Throughout the theater, the theater army continues to request and receive Army forces and expand
  theater bases in and outside the JOA. During conflict, the theater army expands the number and capability of
  its subordinate commands to meet the demand for operations. Concurrently, military engagement, security
  cooperation, and deterrence outside the JOA continues.
  3-112. Protracted campaigns that include large-scale combat operations cause the theater army to expand
  to support Army, joint, and multinational forces. This occurs as the combatant commander adapts the joint
  command and control mechanism to the demands of the campaign. This may result in the theater army
  deploying the contingency command post to perform its joint roles as the JTF headquarters or the JFLCC.
  The contingency command post cannot adequately perform any joint roles without significant reorganization
  and retraining. Regardless, the theater army as the ASCC will maintain its AOR-wide focus while developing
  a mature support structure in the JOA.
  3-113. Because of the limited capability of the contingency command post, the theater army may request a
  corps to serve as the land component commander when the required land force is a corps or smaller. However,
  when large-scale combat operations involving more than one friendly corps are likely, the theater army
  requests the constitution of a field army.
  3-114. When a field army is constituted, it performs operational ARFOR tasks, serves as the JFLCC, and
  is the Army component of the joint force in an AO. The theater army will then exercise ADCON over the
  field army and its subordinate Army forces. This includes 10 USC, common-user logistics, ASOS, Army
  executive agent responsibilities, and sustainment and medical support for Army and joint forces operating in
  the JOA or the theater of operations where the field army is assigned.
  3-115. Regardless if the theater army or a field army is the land component commander, the theater army
  plans for operations that follow armed conflict. As early as possible, the theater army develops plans and
  requests for forces for approval by the combatant commander. Planning for the transition after a conflict
  requires intensive coordination with the Department of the Army, supporting theater armies, the ARFOR,
  and theater-level commands such as the TSC. The return to competition often requires different Army
  capabilities and headquarters from those required for the conflict.
  3-116. The return to competition marks a shift in focus from sustained combat operations to consolidating
  gains through decisive action to establish a secure environment, provide essential government services,
  emergency infrastructure reconstruction, and humanitarian relief. The shift in focus may require different and
  additional capabilities than those used during large-scale combat, requiring the theater army to plan and
  request forces appropriate for the desired end state.
  3-117. The theater army will also begin to develop redeployment plans in conjunction with the geographic
  combatant command staff and USTRANSCOM for Army units no longer required. Overall, the theater army
  adjusts its theater posture in anticipation of the return to competition. Once consolidation of gains has allowed
  for the transition of control to legitimate authorities, the cycle is complete and the combatant command