text: Chapter 6
  (cid:122) Retaining decisive terrain or denying a vital area to an enemy force.
  (cid:122) Attritting or fixing an enemy force as a prelude to the offense.
  (cid:122) Countering enemy action.
  (cid:122) Accepting risk in one area to create offensive opportunities elsewhere.
  6-174. There are many potential conditions for defensive operations. They include—
  (cid:122) Enemy aggression initiating armed conflict requires forward-stationed friendly forces to defend to
  buy time and conserve combat power until reinforced.
  (cid:122) Offensive operations culminate and the commander needs to build combat power while countering
  enemy offensive operations.
  (cid:122) A unit is assigned an economy of force defensive role as a supporting effort.
  (cid:122) The higher echelon headquarters directs a mission to defend an area, population, key
  infrastructure, or other key terrain in support of the overall course of action.
  (cid:122) U.S. forces accomplish all objectives and transition to a defense to deter future enemy aggression.
  6-175. The key to a successful corps or division defense is a concept of operations that allows defensive
  forces to break the enemy’s momentum and seize the initiative. Surprise is as important in defense as in
  offense, and the defensive concept should avoid obvious dispositions and techniques. When executing a
  defense, commanders orchestrate combat power from all available domains to synchronize effects at a
  decisive place and time that results in the enemy’s defeat. Commanders decide where to concentrate combat
  power and where to accept risk. Success may require that a defending unit exploit opportunities to seize the
  initiative, such as a spoiling attack or counterattack.
  6-176. Time is often the most important resource for defending forces. The enemy chooses the time and
  location for its attack, so the amount of time friendly units have to prepare a defense is often unknown and
  usually inadequate. Defending corps and divisions must have a sense of urgency to complete their planning,
  coordinating, rehearsing, and conducting information collection. Their subordinate units need time to develop
  engagement areas by preparing battle positions, pre-positioning sustainment assets, and emplacing obstacles.
  Taken together this means that strict adherence to priorities of work and priorities of effort is critical to time
  management.
  6-177. Defending commanders seek to create more time to prepare an effective defense. A corps or division
  commander may task-organize and resource a security force for employment in the security area to guard or
  cover main battle area forces as a means to create additional preparation time and prevent surprise.
  Commanders may also launch spoiling attacks, raids, or feints to disorganize enemy preparations and gain
  more time to prepare. A defender continually attacks enemy forces in depth with joint and Army fires and
  aviation to attrit the enemy force and disrupt its scheme of maneuver. Friendly conventional and special
  operations forces can slow an enemy attack by complicating the enemy force’s movements and supply.
  Uncertainty as to when or where enemy forces will attack requires a commander to maintain a larger reserve.
  6-178. A successful defense requires the integration and synchronization of all available assets. The
  defending commander assigns missions, allocates forces (including the reserve), and apportions functional
  and multifunctional support and sustainment resources within the construct of main and supporting efforts.
  The commander determines where to concentrate defensive efforts and where to accept risks based on the
  results of intelligence preparation of the battlefield. This determination includes accounting for the enemy’s
  reconnaissance and surveillance efforts and the vulnerability of friendly troop concentrations to massed
  enemy fires. Commanders strive to counter enemy attacks by accounting for its capabilities in each domain
  that can influence friendly forces.
  CHARACTERISTICS OF THE DEFENSE
  6-179. Successful defenses share some important characteristics. They include—
  (cid:122) Disruption—deceiving or destroying enemy reconnaissance forces, breaking up combat
  formations, separating echelons, and impeding an enemy force’s ability to synchronize its
  combined arms.
  (cid:122) Flexibility—developing plans that anticipate a range of enemy actions and allocate resources
  accordingly.