text: Chapter 3
  the theater army to focus on theater-level matters and allows it to synchronize competition and preparation
  for combat activities across the GCC’s entire AOR.
  3-140. During competition, the field army can deter threats and prepare to transition to large-scale combat
  operations when the risk for immediate, multi-corps, large-scale combat is high. With joint force
  augmentation, the field army may also serve as the JFLCC during competition.
  FIELD ARMY IN CONFLICT
  3-141. During armed conflict, the field army, as the ARFOR, may also serve as the joint force land
  component. As the JFLCC, the field army commands and controls multiple corps to enable synchronization
  of their maneuver and effects across a land AO. The field army is best suited to serve as the JFLCC during
  large-scale combat that involves multiple corps-sized formations against peer threats, because of its ability
  to include units of other Services or of allied forces and exercise operational as well as tactical
  responsibilities.
  3-142. As the joint force and/or coalition land component commander, the field army requires joint and/or
  multinational headquarters augmentation. However, once established, the field army as the joint force land
  component normally becomes the supported commander in the land AO of the JTF JOA. It will incorporate
  additional multinational units and designate subordinate corps’ areas of operations. The field army
  headquarters has the authority to designate target priorities, effects, and timing of fires and maneuver in the
  assigned land component AO.
  3-143. Field armies are primary units of operational maneuver, conducting the decisive operations of the
  land campaign. When operating as the land component of a joint force, field armies may be charged with
  planning and conducting the land campaign in an area of operations.
  3-144. Field army commanders employ subordinate corps to concentrate combat power, to accept or decline
  battle, and to exploit the outcome of tactical actions. Field armies and equivalent organizations are primarily
  operational headquarters. They may establish priorities for sustainment among their subordinate forces. In
  contingency operations, the field army may assume responsibility for the logistic support of Army forces in
  the field. In such an operation, the field army would require the assignment of support organizations from
  the theater army or unified command. (See JP 3-31 for more information on unified commands.)