Human conflicts of many kinds occur throughout the world. Within the broad spectrum of these conflicts, our concern in this document is narrowed to those that involve military conflict, and within this still vast category, the subject is narrowed to warfare, and then further narrowed to the subset of warfare called military combat.

Whether or not the waging of war and combat is an innate characteristic of humans is not addressed in this work. Warfare is accepted and legally sanctioned in human society, at least for defensive purposes. And since the history of the species has demonstrated that wars have arisen time and again despite attempts to end them, warfare, and combat as its cutting edge, are important subjects for study.

By the term military conflict we mean an antagonistic situation between two or more parties in which military forces and weaponry of each of the parties are used or are available for use if needed. The term military forces means not only formally constituted armed forces, but any body of persons that combines to wage or threaten aggressive or defensive action vis-à-vis another group. Thus paramilitary units that may be created without a formal tie to a recognized political entity are military forces that can engage in military conflict, often but not always localized and limited in scope and sometimes carried out under covert or overt sponsorship of a nation. Similarly, counterinsurgency and counterintelligence forces engaged in defense of a political entity are military forces within our meaning. In the more general case, military forces are responsive to nation states and are formally organized by those states into units with weapons and uniforms. And in the more general case, these forces may engage in military conflict in the form of wars, campaigns, battles, engagements, sieges, blockades, and also in forms of military conflict short of outright hostilities, such as shows of force, policing, and peacekeeping.

In illustrating the scope of military conflict we can say at the outset that the boundary of what is included cannot be defined by the line between peace and war, since many forms of military conflict occur during periods not considered times of war.

Figure 1 portrays the spectrum of human conflict and, as a subset, the spectrum of military conflict. Two aspects are shown: the levels of violence and the geographical extent. The levels of violence blend and overlap without clear distinction of one from another. Terrorism and sabotage, for example, can range from civilian person-to-person and group-to-group conflicts to international and ethnic conflicts. The geographical extent of conflicts similarly can stretch from localized areas to near-global scope. The second World War was violent conflict waged over much of the globe for several years; the United States attack against Libya in 1986 was violent conflict confined to a small geographical area for a short time.

The magnitude and geographical extent of military conflict are sometimes distinguished by the terms strategic level and tactical level. These terms are relative and can be misleading when applied to levels of military conflict. In the common meaning, strategy and strategic level refer to the broad, overall concepts and planning for a military conflict, whereas tactics and tactical level refer to the more detailed implementation measures in response to the strategy. A strategy is a plan, with a specifically expressed goal, to execute national or other political policies. Strategic level is therefore usually associated with national authorities and theater-level commands. Most of what takes place in combat is generally considered the tactical level. Recently another term has been added to distinguish military activity at the level between strategic and tactical. This is called the operational level.

Yet in contrast to these common uses of the terms, there are frequent references to the strategy of a small part of a military conflict or the strategy used in conducting a single battle. And certainly at each echelon in warfare, a commander has the equivalent of his strategy for conducting operations at that echelon, even though he may not use that term. Because of this variability in meaning, we have not used the labels strategy and tactics as hard and fast distinctions for levels of military conflict. In regard to the operational level of warfare, we prefer the term campaign because of its wider usage over many years. Campaigns and operations (or operational art) both refer to the activities conducted to effect a strategy (in the common use of that term), their product being the positioning, maneuvering and sustaining of forces that occurs prior to—and also includes—active combat.

3.1.5 Military Combat within the Totality of Conflict

Figure 2 depicts the place of military combat within the totality of human conflict. War is the principal context within which combat occurs (but not the only context, as combat can occur in the absence of formal warfare). War means, in the broadest sense, all the adversarial activities of two (or more) hostile parties to a military conflict. This includes political, economic, and diplomatic actions conducted during the conflict together with actions carried out by military forces. Within wars there can be one or more campaigns, normally of shorter duration and involving a smaller set of forces than are engaged in the war. Campaign means the coordinated movement, positioning, and preparation of forces to attain a specified objective, which is responsive to a broader war objective. The campaign may involve a series of stages carried out sequentially or in parallel, and it ends when the objective is achieved or is deemed unattainable. A campaign ordinarily leads to and includes one or more combat situations or threats of combat (the definition of combat is presented below).

Within a particular combat there will be one or more engagements, which can take place simultaneously or be separated in time. An engagement is localized, heightened activity during combat that involves intense use of deadly force between the opposing sides. There is no clear-cut boundary that separates an engagement from other activity during combat; the only distinction is that of heightened action in a localized space over a relatively brief time span. Firefight is a synonym for engagement. Within engagements there will normally be many shorter spasms of fighting between two entities—individuals, small units, armored vehicles, aircraft, ships—which we call duels for lack of a more concise label.

The combination of duels, engagements, combat, and campaigns comprises a continuum of war activity. Within this continuum, events are episodic rather than continuous. There is not an unbroken flow of duels one after the other, nor of engagements, combat, or campaigns.

The term battle is commonly used in a context that equates to our term combat yet sometimes is broader in scope and sometimes approximates our engagement. Because of this spread of meanings, we have not used battle to designate a specific category of military conflict.

We include within our definition the threat of deadly force in addition to its actual use. Admittedly this may add a degree of fuzziness. A situation in which force is threatened but not used is an unusual case, though it has occurred in history. We include such a case within our definition only where the initial intent by both sides was to employ deadly force and preparations were made to those ends, even though the intent was later changed by one side before deadly force was brought to bear. We exclude the case where one side from the outset chooses not to oppose the enemy (and cannot be forced into the contest); and we exclude the case where one side absents itself from the scene, leaving the other party to carry out its mission unopposed.

Throughout, the word combat by itself is used as a noun or adjective to mean the totality of activity that is included within our definition of the term. The words a combat and the combat are used as nouns to refer to a particular combat from beginning to end.

Our definition of combat includes a beginning, an active phase, and an ending. The active phase starts when violent means are employed by either side against the opponent. The beginning phase includes the preparatory actions immediately preceding the active phase after a decision has been made by either side to proceed with combat. These include such actions as developing plans and disseminating orders, positioning forces and supplies, setting up protective measures, scouting and other intelligence gathering, and mentally preparing troops. In some cases (an ambush, for instance, or a submarine stalking and executing a surprise attack against an enemy warship) one side has virtually no time to make preparations; under our definition combat has begun when the other side sets up the ambush or begins the stalking. In cases where neither side has time to prepare, combat begins with the active phase. The end of combat is marked by the cessation of interaction by both sides—especially the use of violent means—and the immediate repositioning and reconstitution of forces in accordance with the situation. One side may have gotten its dose of fighting and be on the run, but combat does not end until its opponent has ceased to pursue. It is clear from this discussion that establishing the boundary as to precisely when any particular combat starts and when it ends is to some extent a matter of choice.

Military combat is normally episodic. From the beginning of the active phase until its end there will usually be periods of intense fighting separated by periods of lower activity during which forces regroup to engage in the next confrontation. Insofar as the reduced activity is merely a pause in the on-going action to achieve a mission, it does not constitute a termination of combat within our definition.

No firm boundary can be established as to the magnitude of forces, the geographical area, or the time duration that is encompassed within the definition of combat. On the smaller side we can consider combat involving only squad- and platoon-size forces, or two ships or aircraft in extended but isolated actions against each other. On the larger side we can include division- and corps-size air-land-amphibious forces, large naval fleets, and massive air assaults. Contiguity of mission is the governing factor more than size or duration. All the forces of each side that are engaged in fulfilling the mission of their side are the forces participating in the combat, whether or not they actually shoot or are in harm’s way. Forces spatially remote from the main combat arena, such as stand-off surveillance aircraft or space-based communications satellites are included when they directly support the mission. The three-day Battle of Gettysburg includes a number of separate instances of combat, as does the Battle of the Somme in 1916 and the Battle of the Bulge in 1944. The Battle of Marathon between Greeks and Persians in 490 BC and the naval Battle of Savo Island in 1942 are single instances of combat.

We likewise establish no bound as to kind of weapon. Any weapon that is potentially lethal or incapacitating is a candidate. Weapons can range from fists, knives and clubs to thermonuclear and biological weapons. The geographical extent and the nature of combat environment are similarly not limited. Combat can occur on land, in the air, at and under the sea, in space, and in any combination of these environments, and it can be confined to a small area or range over a broad expanse in three dimensions.

In describing combat as the cutting edge of warfare with a discrete beginning and end (granting some looseness as to starting and ending points), we do not mean to isolate combat from the military conflict of which it is part. At all times, from beginning to end, combat and all combatants are affected by the broader context in which combat is set, and what happens in combat feeds back to affect that broader context. This broader context includes everything outside the combat arena that has any influence on what is done by either side.

Combat is always subservient to the wider perspective of the campaign and the war, and beyond that to the political interests and to the populace at large. The external context will impose constraints and impetus on the conduct of combatants. Societal culture can be a powerful influence on individuals, collectively and individually. This broader context affects the purpose, values, and mission; and the results of combat are fed back as influences on the campaign and the war.

Granting the influences of the external context, it is nevertheless in the crucible of combat that campaigns can become successful and wars can be brought to a favorable military end. And granting that in warfare, the time spent and number of persons engaging in combat are a small fraction of the total, it is in combat that critical events are made to happen.

Of all human endeavors, combat is perhaps the most intense for its participants. Each puts his life and that of his opponent in jeopardy and dictates that many on each side must give up their lives for a sometimes remote, abstract cause. While not every combat will have a decisive outcome, the high-risk, high-stakes nature of combat sets it apart as the crucible where decisions in war are settled.