text: Chapter 2
  both the operation and the sustainment assets must be weighed carefully and reassessed as the situation
  develops.
  2-119. Command and support relationships provide the basis for unity of command and unity of effort in
  operations. Within planning, commanders are responsible for task organizing the force and prioritizing efforts
  as part of the operations process. Task organizing is the act of configuring an operating force, support staff,
  or sustainment package to meet a unique task or mission. This allows commanders to allocate resources to
  weight the main effort.
  2-120. Commanders recognize that effectiveness is built on mutual trust and confidence between superior,
  subordinate, supporting, and supported organizations. This trust and confidence is developed through
  relationships. Generally, the longer a relationship lasts, a greater degree of trust and confidence results.
  Authorities and responsibilities are typically well known between organizations that have had a long-term
  habitual relationship. However, the nature of the sustainment structure at EAB forces commanders to place
  organizations in unfamiliar situations. In this instance, where trust and confidence between organizations is
  limited, command and support relationships establish baseline doctrinal authorities and responsibilities upon
  which unfamiliar organizations can operate.
  2-121. Command and support relationships vary between different units and echelons. The types of
  command and support relationships established are dependent on the mission and the degree of authority a
  commander wishes to establish between subordinate units.
  ARMY COMMAND RELATIONSHIPS
  2-122. The five Army command relationships are: organic, assigned, attached, OPCON, and TACON. Each
  relationship has specific authorities and responsibilities. Army command relationships identify the degree of
  control of the gaining Army commander. Command relationships unify effort and enable maximum
  flexibility for commanders to use subordinate forces. The expected duration of a command relationship
  normally dictates the type of command relationship between the headquarters involved and identifies the
  degree of support the gaining and losing Army commanders provide.
  2-123. Commanders designate command relationships to subordinate units in OPORDs. The designation
  must indicate the headquarters under which a subordinate unit is placed, the specific command relationship
  designated, and the duration of the relationship. The duration may be based on time, duration of a phase, or
  on achieving an objective. This information is included in the “Task Organization” paragraph of the OPORD.
  If the task organization is long or complicated, commanders may place it in annex A of the order. Table 2-2
  displays the Army command inherent responsibilities. JP 3-0 discusses command relationships for the joint
  force.