text: PART THREE
  Defensive Operations
  Commanders use defensive operations to destroy enemy forces; to retain terrain,
  resources, and population centers; and to regain the initiative. Part Three consists of
  four chapters that describe the fundamentals of the defense and the three types of
  defensive operations—area defense, mobile defense, and retrograde.
  Chapter 8
  The Defense
  Defensive actions are operations that create conditions for the offense that allow Army
  forces to regain the initiative. This chapter covers the purpose, characteristics, types,
  common control measures, common planning considerations, and transitions for the
  defense.
  PURPOSE OF THE DEFENSE
  8-1. While the offense is more decisive, the defense is usually stronger. However, the conduct of the defense
  alone normally cannot determine the outcome of battles. The purpose of the defense is to create conditions
  for the offense that allow Army forces to regain the initiative. Other reasons for conducting the defense
  include—
  * Countering enemy action.
  * Retaining decisive terrain or denying a vital area to an enemy.
  * Attriting or fixing an enemy as a prelude to the offense.
  * Increasing an enemy’s vulnerability by forcing an enemy commander to concentrate subordinate
  forces.
  8-2. A defensive operation is an operation to defeat an enemy attack, gain time, economize forces, and
  develop conditions favorable for offensive or stability operations. The inherent strengths of the defense are
  the defender’s ability to occupy positions before an attack and use the available time to improve those
  defenses. A defending force stops improving its defensive preparations only when it retrogrades or begins to
  engage enemy forces. A defending force continuously takes opportunities afforded by lulls in action to
  improve its positions and repair combat damage during execution of the defense.
  8-3. A defending force does not wait passively to be attacked. A defending force aggressively seeks ways
  of attriting and weakening enemy forces before close combat begins. A defending force maneuvers to place
  enemy forces in a position of disadvantage and attacks those enemy forces at every opportunity. The static
  and mobile elements of a defense combine to deprive enemy forces of the initiative. A defending force
  contains enemy forces while seeking every opportunity to transition to the offense.
  8-4. Units can visualize their defensive assigned area using a main battle area (MBA), a security area,
  forward edge of the battle area (FEBA), the FLOT, and rear area. The main battle area is the area where
  the commander intends to deploy the bulk of their unit to defeat an attacking enemy. The security area