Two recent articles published on The Strategy Bridge have attempted to make sense of the term "Limited War." Both accept that wars may range in scale from limited to total, and both end up viewing the measurement of this scale from the perspective of the percentage of available resources expended by the belligerents.
In the first article, "The Return of Limited War," Ian Bertram argues that limited wars are a function of the cost. Thus, in the 18th century the price of soldiers was too high to risk losing them and today the price of modern weapon systems is too expensive to risk losing too many of them. However, other than a side-remark about this perhaps being politically useful because it might reduce the number of wars a belligerent (in his case the U.S.) is willing to participate in, Bertram does not discuss the utility of this concept.
Timur Nersesov, responding to Bertram's article in "What Size is My War?," raises two very pertinent questions:
If the measure of limited war is the fraction of an entity's capability expended, how does one deal with relativity—a limited war for the US might be a total war for its rival?
So what? What utility is there in measuring the limitedness or totality of a war? Especially if one does not solve the issue of relativity.
Nersesov discusses the first question but does not actually answer it. As to the second, his answer is that "the notion of 'limited war' [is] only useful in the sense of describing objectives and political theater. It does not provide an analytical basis for evaluating potential conflicts in any objective sense or making predictions on the nature of future wars." In other words—it does not have much practical value for the political and military decision-maker, perhaps some for the curious onlooker and historian.
Bertram and Nersesov both fail to address a third question: whereas 'totality' is an absolute measure—this is the highest effort a particular entity can achieve—'limitedness' is in itself a wide scale. Or in other words: how limited is limited? Relativity is not only between the rivals in the same war—it is also between the level of effort required by the same belligerent in different wars. Thus, the American wars in Grenada (1983), Panama (1989–1990), Kuwait-Iraq (1991), Kosovo (1999) and again Iraq (2003), were all 'limited wars' for the U.S., but each was very different in the effort expended relative to the potential capability of the U.S.
This article will propose a different viewpoint—that defining the size of a war on a more objective scale provides the decision-makers with a decision-making tool. Before explaining the utility achieved this raises two additional questions:
What is war?
What is the defining measurement that provides utility?
There is no accepted definition for war. Having combed through a list of definitions suggested over the past couple of hundred years, attempting to divine on what points they all agree, and perusing historical experience I have concluded that in fact two complementary definitions are necessary. The first definition attempts to describe what behavior is war: deliberate reciprocal violence between groups of people. However, this definition is not sufficient. In order to separate unacceptable violence from acceptable violence communities construct rules—therefore, a legal definition is required to declare when and against whom violence is permitted and when and against whom it is not permitted.
This requires a separate definition for purposes of legality: a legal state declared by the appropriate authority. These two definitions overlap, but each also has an area of independence. In other words, there are wars to which both definitions apply, there are wars in which violence is committed but not officially declared to be war and there are wars which are declared but not fought. Thus, for example, the U.S. military interventions in Korea and Vietnam were not officially declared to be wars, whereas both its wars against Iraq were sanctioned officially by Congress. Conversely, Iraq and Israel have been officially in an active state of war since May 15th 1948—unlike the other belligerent Arab states, Iraq has consistently refused to sign even a ceasefire agreement with Israel. However, actual fighting between the two states has been virtually non-existent. All told, in 68.5 years of officially declared belligerence, Iraqis and Israelis actually fought each other for a combined total of perhaps four months—mostly in 1948.
Only the descriptive definition is relevant to the issue of this article because it provides the basis for finding an objective measurement—war is not about the groups conducting it, but about the violent interaction between them. Not the scale of effort expended by each group is the measure of limitedness or totality of war as such, but rather the intensity of the reciprocal violence achieved by that effort. The intensity of reciprocal violence being the number of actual fighting incidents conducted in a given fraction of time multiplied by the size of each separate incident.
The first benefit for the decision-maker in using this particular measure is that it provides a tool for assessing a belligerent's ability to create and maintain the effort required to achieve that level of intensity. Thus, some potential belligerents are physically capable of conducting only low intensity wars, whereas others are physically capable of conducting wars of higher intensity. A belligerent capable of conducting a higher intensity war can also conduct a lower intensity war and can therefore choose the intensity it wishes to employ as per political aims and constraints. The actual intensity chosen by the belligerents depends on the political goals, the political, economic and cultural constraints, geography, etc. Another important factor is the enemy—each side strives to conduct the war at the intensity it assesses to be most advantageous and compel the rival to fight at that intensity too. Thus, the U.S. would have preferred a high intensity war in Vietnam, whereas the Communists preferred a low to medium intensity war and managed to manipulate the political and cultural constraints of their adversary to compel the U.S. to fight the war at the intensity preferred by them.
The second benefit of this model of decision making is that different intensities of war require different strategies to achieve victory, so identifying the intensity or choosing it provides campaign planners with useful information. The higher the intensity of a war, the higher the probability that it will be decided by the reduction inflicted on either rival's war-making capability (casualties, damage to equipment and infrastructure and loss of territory). When one side is physically destroyed, or realizes that the current trend of fighting is in that direction, the war will usually end. Conversely, the lower the intensity of a war, the lower the physical damage inflicted to the rivals and therefore the higher the probability that it will be decided by the level of psychological fatigue inflicted on them. Having chosen or identified the intensity, the planners can deduce the operational actions most suited to defeating the enemy.
So how do we measure intensity? A simple scale provides five basic levels of intensity: zero (there are no appreciable acts of violence—war, legally declared or not, does not exist); very low intensity, low intensity, medium intensity, and high intensity. In fact, each of these includes an internal variety of intensities and the problem of discerning between them is the same as trying to discern between shades of grey. Everyone can easily see the difference between light grey and dark grey, and with slightly more effort between light grey and medium grey or medium grey and dark grey. The problem is finding the crossover points. For the purposes of this article, intensity of fighting is defined as a interaction of the number of incidents in a given fraction of time by the size of each of these incidents. So, theoretically, all that needs to be done is to decide the number at which a given intensity crosses over into the adjacent intensity.
The reality is more complex for decision-makers, it is not simply a matter of numbers and such a model of thinking is not meant to be an exhaustive nor deterministic consideration of the intensity of war. However, it might just be good enough to describe the leverage that decision-makers have in assessing the kind of war they are in. We are not discussing a scientific separation between phenomena. In different contexts the same number might mean different things. In other words, the crossover from a particular intensity to the next is not a clear boundary, but a nuanced appreciation of the situation. Sometimes it is more a matter of soft emotions than of hard facts. An example of this problem is the Israel Defense Force’s (IDF) difficulty in understanding the operational situation it was facing in the Second Lebanon War (2006)—expecting an enemy conducting low intensity irregular warfare, IDF commanders were surprised to find themselves fighting an enemy conducting a mix of irregular and regular warfare at an intensity higher than expected. In analytical retrospect it is clear that Hezbollah had begun to build the capability to conduct medium intensity defensive operations and so the IDF's operational plan foundered as it tried to identify and understand the unexpected situation and adapt accordingly. Adding to the difficulty to adapt was the inability to determine if the threshold between the higher level of low intensity fighting and the lower level of medium intensity fighting had been crossed. Thus, even after the war some IDF commanders continued to refer to it in terms appropriate to low intensity operations—the realization of what had happened only sinking in gradually. However, having learned the lesson, in Operations Cast Lead (December 2008-January 2009) and Protective Edge (2014) the IDF's plans were framed to take into account the creation of similar capabilities by Hamas and were more successful. In Cast Lead the intensity of fighting remained low, in Protective Edge it escalated to medium. Being more aware of the possibilities, the IDF planners were better able to adjust actions to meet strategic requirements and yet, even then the discourse was sometimes problematic describing Hamas defensive actions in terms better suited to low intensity warfare. Having admitted the problem of the fuzzy edges, it is nonetheless clear that there are clear actionable differences between intensities.
To summarize: defining the level of limitedness or totality of a war by the percentage of effort expended by the belligerents is indeed not a useful construct for decision-makers. However, using the intensity of the violent interaction between the belligerents as the basis for defining the limitedness or totality of war, though not simple and straightforward, provides some benefits for the strategic planners. Choosing or being compelled to fight a particular intensity of war is a grand-strategic issue—depending on the political, economic, cultural, and military capabilities and constraints developed by the rival communities at large. It determines the military objectives and methods employed. Therefore it behooves decision-makers to strive to choose an intensity that provides them with the most advantages vis-à-vis the enemy and, if possible, to prevent the enemy from compelling them to fight at the intensity it chooses.
Eado Hecht is a Research Fellow at the Begin–Sadat Center for Strategic Studies (BESA Center). He teaches military history and military theory at a number of Israeli universities and Israel Defense Force courses. He is also an associate editor at The Journal of Military Operations.
 Ian Bertram, "The Return of Limited War," The Strategy Bridge, http://thestrategybridge.org/the-bridge/2016/9/13/the-return-of-limited-war; Timur Nersesov, "What Size is My War? Examining the Concepts of Total and Limited War," The Strategy Bridge, http://thestrategybridge.org/the-bridge/2016/11/3/what-size-is-my-war-examining-the-concepts-of-total-and-limited-war.
 In 1973, to prevent a recurrence of a presidential decision to conduct actual war without an official declaration, Congress passed the War Powers Resolution, that limits the authority of the President to employ military forces in fighting without Congressional approval.
 A few months of combat in summer 1948, and since then occasional Iraqi participation in some of the later Arab-Israeli Wars—the last being in 1973, the Israeli bombing of the Iraqi nuclear reactor in 1981 and the firing of approximately 40 missiles from Iraq into Israel in 1991.
 This mix led to the invention of the term 'hybrid warfare.' Frank G. Hoffman, Conflict in the 21st Century: The Rise of Hybrid Warfare, Potomac Institute for Policy Studies, 2007. The IDF suffered from a number of other problems as well, but this issue was central and affected the other issues too.