text: Defense
  constraints,throughout the depth of the base camp area of operations to meet security and defense objectives.
  Commanders and staff with base camp security and defense responsibilities plan,coordinate,and synchronize
  actions using integrating processes to ensure full integration of their area security and base defense plans.
  (SeeATP 3-37.10for additional information.)
  7-85. Refer to chapter 6 for a discussion of the following supporting tasks of the protection warfighting
  function:
  (cid:122) Implement physical security procedures.
  (cid:122) Apply antiterrorism measures.
  (cid:122) Provide explosive ordnance disposal support.
  (cid:122) Conduct personnel recovery.
  (cid:122) Conduct populace and resource control.
  (cid:122) Conduct risk management(RM).
  SECTION III – FORMS OF THE DEFENSE
  7-86. The three forms of the defense (defense of a linear obstacle, perimeter defense, and reverse-slope
  defense) have special purposes and require special planning and execution. The three forms of the defense
  provide distinct advantages for the BCT and its subordinate units and apply to the area defense and the
  operations of the fixing force during amobile defense. (SeeFM 3-90-1 for additional information.)
  DEFENSE OF A LINEAR OBSTACLE
  7-87. The defense of a linear obstacle usually forces the enemy to deploy,concentrate forces,and conduct
  breaching operations. A defense of a linear obstacle generally favors the use of a forward defense (see
  paragraph 7-128). The defending unit constructs obstacles to stop the enemy forces and channel them into
  planned EAs. Maintaining the integrity of the linear obstacle is the key to this type of defense. When attacked,
  the defending force isolates the enemy, conducts counterattacks, and delivers fires onto the concentrated
  force to defeat attempts to breach the obstacle.
  7-88. A defense of a linear obstacle often is used as part of an economy of force measure. In this situation,
  the defending force cannot allow the enemy to build up its forces on the friendly side of the obstacle because
  it may lack the required combat power to defeat the enemy forces. As forces to counterattack and destroy the
  enemy may not be available immediately;defending forces must be able to—
  (cid:122) Detect enemy penetrations early enough so that local counterattacks can defeat them.
  (cid:122) Defend after being isolated.
  (cid:122) Use reconnaissance elements,sniper teams,and other elements to detect enemy forces andcall in
  fires.
  (cid:122) Bring the fight to the enemy side of the obstacle to destroy its forces and disrupt enemy
  preparations.
  (cid:122) Use fires to their maximum effect.
  (cid:122) Use its mobility to concentrate combat power.
  Defense of a Linear Obstacle: Fredericksburg,VA 1862
  By December 13,1862,Confederate General Robert E. Lee established a strong defensive
  position behind the Rappahannock River in Northern Virginia against Union forces (see
  figure 7-4on page7-20). He only lightly defended the actual river line because theUnion
  army artillery dominated both sides of the river. His main defensive position was directly
  west along a line of hills. The area between the river and the hills was generally open with
  scattered woods and streams or canals. The most concealed area was the town of
  Fredericksburg.
  Early on December 13, the Union army crossed the river and formed for the attack. The
  plan was to conduct the main attack to the south with a supporting attack to the north.
  Despite repeated attacks, the Union forces were repulsed everywhere. Union casualties