text: The Principles of War
  force, a reciprocal of mass, demands the judicious employment and distribution of forces. It requires
  deliberately accepting risk in selected areas to achieve relative superiority—or overwhelming effects—in
  others. Economy of force involves the discriminating employment and distribution of forces. Commanders
  never leave any subordinate element without a purpose. The allocation of available combat power to tasks
  such as limited attacks, defense, delays, deception, or even retrograde operations is measured to achieve mass
  elsewhere. Accepting risk through economy of force creates opportunities to exploit.
  MANEUVER
  A-11. Maneuver is coordinated movement and fire in relation to enemy forces to put them at a disadvantage
  with the least cost to friendly forces. Firepower, mobility, protection, and leadership enable maneuver.
  Intelligence focuses–and sustainment enables–maneuver over distance and time. In the strategic sense,
  maneuver has three interrelated characteristics: flexibility, mobility, and maneuverability. Flexibility must
  characterize thought, plans, and operations to maintain the initiative during changing conditions with an
  adaptive enemy. Flexibility enhances rapid reaction to unforeseen circumstances. Mobility is the capacity to
  respond rapidly in crisis, move across strategic distances, and move to a position to conduct operational- and
  tactical-level maneuver.
  A-12. Tactically, maneuver is about moving forces and firepower into better positions relative to enemy
  forces to gain a compelling advantage: the ability to destroy enemy forces unless they reposition while
  making friendly forces more difficult to fix and destroy. It contributes to seizing, retaining, and exploiting
  the initiative and preserving freedom of action. Maneuver allows commanders to concentrate and disperse
  forces to keep enemy forces off balance and out of position. Conversely, limiting enemy maneuver keeps
  them in positions of disadvantage, ideally leading to their eventual destruction or defeat at the time and place
  of the friendly commander's choice.
  UNITY OF COMMAND
  A-13. This principle ensures that all efforts focus on a common goal. Unity of command means that a single
  commander coordinates the actions of all forces toward a common objective. Cooperation may produce
  coordination, but giving a single commander the required authority is the most effective way to achieve unity
  of effort. Ultimately a single commander is responsible for an objective at each echelon. Diffusing
  responsibility otherwise creates misunderstandings during the stress of combat. Commanders deny enemy
  forces unity of command by destroying or disrupting enemy C2, taking action to isolate enemy echelons, and
  exploiting boundaries between enemy formations. This makes coordination of forces, collaboration of
  planning, and cohesive operations more challenging for enemy commanders. Denying enemy forces unity of
  command is crucial to denying them the ability to exploit emerging tactical opportunities.
  A-14. The joint, interagency, and multinational nature of operations creates situations where the commander
  does not directly control all organizations in the area of operations (AO). Achieving unity of effort under
  such conditions becomes the goal, which requires coordination and collaboration among forces-even though
  they may not be part of the command structure-toward a commonly recognized objective.
  SECURITY
  A-15. Security enhances freedom of action by protecting and preserving combat power while reducing
  friendly vulnerability to surprise. Every Army formation is responsible for its own security. The application
  of the principle of security does not suggest over-cautiousness or avoidance of risk but rather the
  unwillingness to cede any advantages to the enemy unnecessary. Security is closely related to the operational
  imperative that friendly forces operate under the assumption that they are under observation and always in
  contact with enemy forces. Security relies on gaining and maintaining enemy contact on friendly terms, and
  it is directly related to the principle of surprise. Preventing surprise by maintaining contact with enemy forces
  enhances security and denies them opportunities to seize the initiative.
  A-16. At the strategic level, security requires active and passive measures to protect Army forces from
  espionage, subversion, and strategic intelligence collection. At the tactical level, it is essential to protection
  and the preservation of combat power. Security results from the protective measures commanders take to
  prevent surprise, observation, detection, interference, espionage, or sabotage.