text: The Defense
  Area Security
  8-127. The enemy will employ of mix of long-range fires, aircraft, cannons, missiles, and rockets, as well
  as ground maneuver and special purpose forces, to attack defending forces, command and control nodes,
  lines of communication (LOCs), sustainment sites, and civilian population centers to disrupt a unit’s defense.
  Units pay attention to area and local security throughout the conduct of the defense. This is especially true
  when the defending unit conducts noncontiguous operations. Units protect their forces and critical assets
  through a variety of measures. Forces conducting area security in the defense can deter, detect, or defeat
  terrorist elements in addition to providing protection from more conventional threats.
  8-128. The success of unit defensive actions may depend on protecting the echelon support area from enemy
  attacks. Units address any early detection and immediate destruction of enemy forces attempting to operate
  in the echelon support area or interdict LOCs between support areas and maneuver forces. Enemy attacks in
  the echelon support area can range in size from individual saboteurs to enemy airborne or air assault insertions
  targeted against key facilities and capabilities. These enemy activities, especially at smaller unit levels, may
  even precede the onset of hostilities and may be almost indistinguishable from terrorist acts.
  8-129. Units clearly define responsibilities for the security of units in the echelon support area. The unit
  designated as responsible for a given echelon support area (for example, the maneuver enhancement brigade
  for the division support area) is responsible for defensive planning and risk mitigation in that area. That unit
  can designate the commanders of tenant units (except medical corps officers) as base and base cluster
  commanders. Those base and base cluster units are responsible for the local security of their respective bases
  and base clusters. The unit responsible for the echelon support area can also designate protection standards
  and defensive readiness conditions for tenant units and units transiting through the area. Higher protection
  standards can affect the ability of those supporting sustainment units to perform their primary mission—
  support the operations of maneuver and other forces. Units coordinate to mitigate effects of security
  operations on the primary functions of the echelon support area.
  8-130. The echelon’s OPSEC program and any deception or survivability efforts should conceal the
  location of the friendly objective, the main effort, the disposition of forces, and the timing of the defense
  from enemy forces or mislead enemy forces regarding this information. These measures prevent enemy forces
  from launching effective spoiling attacks.
  8-131. Planners determine how military police elements supporting the defending unit enhance unit
  protection capabilities by conducting area security (including reconnaissance, surveillance, base security,
  protective services, secure routes and convoys, and physical security measures) inside and outside the echelon
  support area. Military police also perform response force operations to defeat Level II threats against bases
  and base clusters located in that support area. Military police maintain contact with Level III threats in the
  echelon support area until a tactical combat force can respond.
  Risk Management
  8-132. The likelihood of fratricide decreases during defensive operations compared to offensive operations.
  During defensive operations, friendly forces are typically stationary and the enemy is maneuvering towards
  them. However, instances for fratricide are typically higher during transitions, such as going on the offense
  or retrograding.
  8-133. During the preparation phase of defensive actions, planning and rehearsals are the primary tools for
  identifying and reducing risk. The types of risks identified determine the type of rehearsal conducted.
  Rehearsals should extend to all levels of command and involve all key players. Considerations for their use
  include—
  * Confirmation briefs to ensure leaders understand what they have been told to do.
  * Backbriefs to ensure subordinates course of actions meets their higher echelon commander’s
  intent.
  * Rehearsals to ensure all Soldiers understand how their organization synchronizes with the rest of
  the friendly forces in offensive operations.