What are the three basic defensive tasks?

The three basic defensive tasks are area defense, mobile defense, and retrograde operations.

Area defense focuses on holding and defending a specific geographical area, ensuring that friendly forces can maintain control over that space against enemy advances. This involves setting up positions, utilizing obstacles, and coordinating fire to repel attackers, while effectively managing resources to sustain the defense.

Mobile defense emphasizes a more fluid and adaptable approach, allowing forces to conduct operations that can maneuver against the enemy. It typically involves accepting some enemy penetration to gain advantageous positions for counterattacks, thereby leveraging the mobility of forces and employing reserves creatively to disrupt and defeat the enemy's assault.

Retrograde operations, on the other hand, involve the organized movement of forces away from the enemy. This task is conducted to preserve combat power while maintaining the ability to re-engage later under more favorable conditions. Retrograde may involve falling back to more defensible positions, conducting delaying actions, or withdrawing forces to regroup and reinforce.

These tasks allow commanders to choose the best approach to defense based on the situation, available forces, and the enemy's actions, making them fundamental concepts in military strategy.