Axiom 2 states that each side in combat seeks to achieve a goal—its mission—which has perceived value. Mission is a pervasive factor that spurs and harnesses combat activity, both stimulating and constraining the action. It acts to bridge the purpose of combat to the outcome. As such it constitutes the primary means for guiding combat in accordance with the grander designs of wars and campaigns.

Mission is a top-down controlling factor which acts through the hierarchical structure of command. The mission given to the highest theater-level echelon becomes the basis for missions assigned to the next echelon, and so on down to the lowest units, each echelon being more circumscribed as to the time and space covered. At the lowest echelons, missions become verbal directions to individuals.

To the extent that the top-down hierarchy of missions is consistent and is comprehended as intended, there is powerful vectoring of an entire force toward the outcome sought by the top of the chain of command. Understanding of the broad purposes of the war effort at all levels serves to foster these conditions. To the extent that missions become muddled, misinterpreted, or evaded, or war purposes are not understood, the vector’s magnitude and direction loses its strength and sharpness.

A combat mission consists of two parts: an objective to be achieved (or task to be performed) and the purpose of achieving the objective (or performing the task). The objective is always stated explicitly, although sometimes in broad terms (and sometimes, in the case of a poorly expressed objective, ambiguously). The purpose is often left to be inferred by subordinate commanders.

In its broader sense, mission expresses the end state of affairs to be achieved during the course of combat—the outcome. In contrast, the statement of mission promulgated in a combat order is often phrased as the actions (usually expressed as tasks) to be accomplished to achieve the outcome, not the outcome itself. In this case the directed actions or tasks serve to imply the outcome, provided they are sufficiently clear. A combat mission statement will normally be a single sentence, but implicit in that brevity will be a vast array of specific actions that the force understands must be taken. Doctrine, training and experience serve to fill in matters not stated, and beyond that, missions are further buttressed by implied national values, goals, and cultural aims. The simple mission of "taking the hill" is understood by all involved as implying many contributing actions for reasons that reach beyond the local situation and for values that, vague as they may be to some, justify the effort and danger. When commanders and individuals cease to see a mission in light of these underlying purposes and values, the mission no longer exerts its directing control over combat, and force effectiveness begins to disintegrate.

Missions are usually received as orders from the next higher command echelon, but they can also be inferred by a commander from his understanding of the policies, goals and intentions of the higher commander and of the entire war effort. In any case the combat commander normally will translate the assigned or assumed mission into a more specific mission statement of the objectives to be attained by his force. The degree of latitude allowed a commander in assuming a mission not explicitly directed from above or in departing from the specifics of an assigned mission will be influenced by what is permissible in doctrine and the personalities of higher and lower commanders. Any combat mission that differs from what was intended by higher echelons risks perturbing the overall control of the war effort—a circumstance that is not necessarily bad if the combat commander has a better appreciation of the local situation and of the context of his combat action within the larger picture.

Values underlie the purposes of war, and the derivative purposes of every combat will likewise have values associated with attaining those purposes. In the end, it is the values that will govern the human and material resource costs expended to achieve the purposes, and hence to fulfill the mission. The relationships among purpose, value, mission, outcome, and cost extend through the hierarchy from top to bottom. The values associated with purposes and missions at the highest echelons are infused as values at lower echelons down to the individual. Compatibility and commonality in the value system throughout the force reinforce the common effort. Nevertheless, values and costs as seen by infantrymen and sailors with their lives at risk are different in particulars from values and costs seen by high level commanders.

The hierarchical relationships among purpose, value, mission, outcome, and cost are illustrated in Figure 3. There can be other conflict levels in addition to the three shown. The purposes, with associated values, at the campaign level flow from those at the war level. At each level, missions derive from the purposes and values at that level and ultimately lead to outcomes that have values associated with them. The values associated with purposes are the a priori values of the outcomes intended, together with the expected costs, whereas the values associated with outcomes are the a posteriori values after resources have actually been expended—after the costs have been counted and weighed in light of what was achieved and of anticipated future events.

The outcome of any single combat, the gains as well as the costs , contributes to the on-going campaign in which the combat is embedded. More remotely, the outcome adds to the war effort. At each level—combat, campaign, and war—the combat outcome is weighed against the post-combat value at that level. The outcome of combat is shared by both sides of the conflict, but the purposes, values, missions, and assessments are unique to each side.

In assessing the outcome of a combat just concluded, a combat commander and his superiors will address how closely the outcome fitted his mission, but they will also weigh the value of the outcome in relation to the value of the combat’s purpose. They may consider the costs as worth the outcome, or the costs as questionable from the point of view of his own force yet acceptable because of the outcome’s contribution to the war effort, or the costs as unacceptable from any point of view. At the campaign level, the outcome of this combat and of all other combat outcomes (as well as noncombat actions) are viewed collectively and the whole is periodically weighed against the purposes and values as seen at that level. The same pattern repeats through all higher levels.

Moreover, the identical pattern of purpose, value, mission, outcome, and cost assessment is also repeated at every lower echelon within the combat force from subordinate commanders down to individuals. At the lowest echelons the assessments are informal or only in the minds of individuals. Thus the pattern of purpose, value, mission, and outcome assessment is constant from the highest to the lowest levels of war.

In no sense can a valid combat assessment by either side be expressed in such simple terms as "win," "lose," or "draw." Combat assessment is never merely a body count or compilation of material destroyed, although these are among many factors to be weighed. It is a complex evaluation seen from different perspectives by many parties. The evaluation is affected by the perceived friendly force situation, the perceived enemy situation and also by the perception of the enemy’s perception. The possible course of future events must be considered—the outcome of one battle becomes part of the initial conditions of the next. Uncertainty is an inevitable component of the assessment, and must be taken into account.

Any assessment has only transitory standing—subsequent events in the campaign and war may convert what initially seemed a favorable combat outcome into, in retrospect, an unfavorable one. In addition, a favorable outcome to one side does not necessarily equate to an unfavorable outcome for the other side. For example, one force could successfully execute its mission of "taking the hill by 1200 hours" while the opposing force was successfully fulfilling its mission of "delaying enemy occupation of the hill until 1100 hours." And even though both sides attained their mission in this example, either or both could have had an adverse outcome if the cost outweighed the value. Combat is not a zero-sum game where one side’s fortune always equals the other’s misfortune.

To reiterate an earlier point, the outcome being assessed is shared by the opponent, and obviously the impact of the outcome upon the enemy is a major part of the assessment on both sides. As will be discussed in more detail later, it is outcome as perceived by the various parties on both sides that is being weighed, and obviously, faulty perceptions about the outcome will lead to faulty assessments.

Assessment does not wait on the conclusion of combat. As combat action unfolds, combat commanders, their subordinates, and their superiors make periodic estimates of the situation and of progress toward mission attainment. Assessment of results during combat enables refinement and redirection of battle activity. Purpose and value continue to be critical determinants, and the balancing of value against cost as combat proceeds is one of the most difficult matters all combatants face—but especially those in command.

The mission hierarchy in its broadest sense is the principal means to vector a force toward the desired goals of warfare. It provides control from the top down through every echelon of the military force to all individuals. At every echelon up and down the chain of command, the mission of that echelon derives from the mission of the next higher echelon. Linked with each mission is a purpose for achieving the mission and an associated value of mission accomplishment. In combat, the mission vectors all combat action, aligning it with the missions and purposes of the war effort. Upon the completion of combat, the outcome is assessed in the light of the post-combat values and costs as seen at (and within) that level and at all higher levels, and the assessments influence further action at all war echelons.