3-69. Usually as part of a larger force, the Infantry platoon conducts the defense performing several integrated and overlapping activities.
3-70. As in the offense, this section divides execution into five steps for discussion purposes. These steps are ─
Gain and maintain enemy contact.
Disrupt the enemy.
Fix the enemy.
3-71. These steps may not occur sequentially; they may occur simultaneously. The first three steps are usually shaping operations and depending on the circumstances, either of the last two steps may be the decisive operation. (Refer to FM 3-90-1 for more information.)
GAIN AND MAINTAIN ENEMY CONTACT
3-72. Gaining and maintaining enemy contact in the face of the enemy’s determined efforts to destroy friendly reconnaissance assets is vital to the success of the defense. As the enemy’s attack begins, the defending unit’s first concerns are to identify committed enemy units’ positions and capabilities, determine the enemy’s intent and direction of attack, and gain time to react. The platoon leader uses the information available to him, in conjunction with military judgment, to determine the point at which the enemy commits to a COA.
3-73. Early detection of the enemy’s decisive operation provides the leader with reaction time to adjust the fixing force’s positions and shape the enemy penetration, which, in turn, provides the time necessary to commit the striking force. The striking force leader requires as close to real-time updates of enemy situation as possible to ensure the striking force engages the enemy at the right location and time.
DISRUPT THE ENEMY
3-74. The leader executes shaping operations to disrupt the enemy regardless of enemy’s location within the area of operation. After making contact with the enemy, the leader seeks to disrupt the enemy’s plan, ability to control forces, and the combined arms team. Ideally, the results of leader’s shaping operations should force a disorganized enemy, whose ability to synchronize its elements has been degraded, to conduct movement to contact against prepared defenses. Once the process of disrupting the attacking enemy begins, it continues throughout the defense.
3-75. Whenever possible the leader sequences these shaping operations, to include enemy command and control warfare, so the impact of effects coincides with the commitment of the striking force. Generating a tempo temporarily paralyzes enemy command and control, the intensity of these shaping operations may increase dramatically on the commitment of the striking force. The leader continues to conduct shaping operations once the striking force commits to prevent enemy forces from outside the operational area from interfering with executing the decisive counterattack.
FIX THE ENEMY
3-76. When conducting an area defense, the leader does everything possible to limit the options available to the enemy. In addition to disrupting the enemy, the leader conducts shaping operations to constrain the enemy into a specific COA, control enemy movements, or fix the enemy in a given location. These actions limit the enemy’s options. While executing these operations, the leader continues to find, and to delay or to eliminate enemy follow-on reserve forces to keep them from entering the main battle area.
3-77. The leader has several options to help fix an attacking enemy force. The leader can design shaping operations, such as securing the flanks and point of a penetration, to fix the enemy and to allow friendly forces to execute decisive maneuver elsewhere.
3-78. The leader uses obstacles covered by fire to fix, to turn, to block, or to disrupt to limit the enemy’s available options. Properly executed obstacles are a result of synthesis of top-down and bottom-up obstacle planning and emplacement. Blocking forces also can affect enemy movement. A blocking force may achieve its mission from a variety of positions depending on METT-TC.
3-79. During the defense, the decisive operation occurs in the main battle area. This is where the effects of shaping operations, coupled with sustaining operations, combine with the decisive operations of the main battle area force to defeat the enemy. The leader’s goal is to prevent the enemy’s increased advance through a combination of fires from prepared positions, obstacles, and possible counterattack.
3-80. Situational understanding is critical in establishing the conditions initiating the striking force’s movement and in determining the general area serving as a focus for counterattacking. It includes identifying those points in time and space where the counterattack proves decisive. A force-oriented objective or an engagement area usually indicates the decisive point.
3-81. The purpose of the defense is to retain terrain and create conditions for a counteroffensive regaining the initiative. The area defense does this by causing the enemy to sustain unacceptable losses short of all decisive objectives. An area defense allows the leader transition to an attack. An area defense also could result in a stalemate with both forces left in contact with each other. Finally, it could result in the defender being overcome by the enemy attack and needing to transition to a retrograde. All decisions to withdraw must take into account the current situation in adjacent defensive areas. Only the leader who ordered the defense can designate a new forward edge battle area or authorize a retrograde.
3-82. The intent of the defense is creating the opportunity to transition to the offense. In a mobile defense, a transitional opportunity generally results from the success of the striking force’s attack. The leader exploits success and attempts to establish conditions for a pursuit if the result of the leader’s assessment of the striking force’s attack shows there are opportunities for future offensive missions. If the conduct of the mobile defense is unsuccessful and enemy retains the initiative, the leader must either reestablish a viable defense or conduct a retrograde.