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Common Tactical Concepts and Echelons 31 July 2019 ADP 3-90 2-11 COMBINED ARMS 2-47. As defined in paragraph 1-21, combined arms includes all capabilities made available to a commander from joint, multinational, interagency, intergovernmental, nongovernmental, and private volunteer organizations. Weapons and units work more effectively when they operate together. No single action, weapon, branch, or warfighting function generates sufficient power by itself to achieve the effects required to prevail. COMMITTED FORCE 2-48. A committed force is a force in contact with an enemy or deployed on a specific mission or course of action, which precludes its employment elsewhere. A force with an on-order mission is considered a committed force. CONCEPT OF OPERATIONS 2-49. The concept of operations is a statement that directs the manner in which subordinate units cooperate to accomplish the mission and establishes the sequence of actions the force will use to achieve the end state (ADP 5-0). The concept of operations expands on the commander’s intent by describing how the commander wants the force to accomplish the mission. The concept of operations promotes general understanding by stating the task that directly accomplishes the mission and the units that will execute it. (See ADP 5-0 for additional information.) DECISIVE ENGAGEMENT 2-50. A decisive engagement is an engagement in which a unit is considered fully committed and cannot maneuver or extricate itself. In the absence of outside assistance, an action must be fought to a conclusion with the forces available. A unit’s mission may result in the unit fighting a decisive engagement, such as when it is tasked to hold key terrain. A unit is considered to be decisively engaged when it is fully committed to that engagement. DEFEAT IN DETAIL 2-51. Defeat in detail is concentrating overwhelming combat power against separate parts of a force rather than defeating the entire force at once. A smaller force can use this technique to achieve success against a larger enemy. Defeat in detail can occur sequentially or separately. For example, a commander can mass overwhelming combat power effects against an enemy element outside the supporting distance of the rest of the enemy force to defeat the enemy element before it can be reinforced. ECONOMY OF FORCE 2-52. Economy of force is the judicious employment and distribution of forces so as to expend the minimum essential combat power on secondary efforts to allocate the maximum possible combat power on primary efforts (JP 3-0). It is a principle of war. Commanders employ economy of force measures (and assume risk) to expend minimum essential combat power on their shaping operations or supporting efforts to provide the maximum possible combat power for their decisive operation or main effort. ENCIRCLEMENT OPERATIONS 2-53. Encirclement operations are operations where one force loses its freedom of maneuver because an opposing force is able to isolate it by controlling all ground lines of communications and reinforcement. A unit can conduct offensive encirclement operations to isolate an enemy force or conduct defensive encirclement operations because of the unit’s isolation from the actions of an enemy force. (For more information on encirclement operations, see FM 3-90-2.)