The likelihood of U.S. forces having to conduct combat in urban areas grows. Understanding critical points and density in urban warfare can mean the difference between success and failure—and between life and death.
Most military men and women have not experienced urban combat. Yet they know enough of war to understand that cities cannot be dealt with in one bite. Understanding which parts are most critical, knowing the character of those components, and discerning how they influence each other are keys to success.
In the urban environment, adversary, innocent noncombatant, and friendly soldier are constantly in close proximity. How can a force engage legitimate targets while leaving others unharmed? How can a commander determine where to focus assets in an operational area consisting of hundreds of buildings with thousands of mobility corridors and tens of thousands of potential enemy hides and firing positions? First, the relative importance of a metropolitan area's component parts must be analyzed and the points at which to selectively apply available assets determined. Second, the appropriate resources must be allocated in the proper quantities, which is made difficult by the heterogeneity of urban environments. A basic physical measure, density, helps to simplify the problem.
Though much of what follows employs combat examples, the suggested approaches have equal applicability to support or stability missions in which combat may not play a part.
Focusing Forces on Critical Points
As recently as World War II, Western armies often had sufficient manpower to envelop and isolate a large urban objective while retaining enough resources to clear the built-up area of enemy forces. Many of today's urban areas have grown in size and complexity to an extent that isolation is impossible. Determining how best to allot limited available capabilities in these cases is essential.
Critical point analysis provides a means of making the vast and complicated manageable. Such points include all terrain, population groups, and other elements that could extraordinarily influence current or future mission accomplishment. More than simply geographic elements, they also may be demographic, encompassing segments of the population or its systems, or functional, providing services such as power or medical services.
Centers of gravity and decisive points are subsets of critical points. A center of gravity is a characteristic, capability, or locality from which a force, organization, or individual derives its freedom of action, physical strength, or will to fight. Decisive points provide a means of unbalancing a center of gravity when the latter is too strong to be attacked directly, is inaccessible, or for some other reason cannot or should not be confronted head on. Dr. James Schneider at the U.S. Army's School of Advanced Military Studies offers an interesting analogy. Considering a center of gravity akin to a very strong wall that cannot be toppled directly, decisive points are the buttresses, footings, and other features that support it. The wall falls through the removal, destruction, or undermining of these elements.
Concurrent with identification of these critical points is determination of the relationships among them. This serves two ends. First, some critical points may be predominant in the sense that destroying, defeating, influencing, or controlling them reduces or eliminates the significance of others. Committing resources against the more influential points would preclude wasting assets on others of lesser importance. Second, the close proximity of infrastructure nodes and the speed of urban communications means that second- and higher-order effects tend to travel faster and be more widespread in built-up areas. Destroying a bridge without first determining the effects of cutting the power lines that run along the structure could result in rendering a portion of the urban area powerless. Should that loss of power close local civilian hospitals, a shortsighted leader might find himself having to provide medical aid to those who otherwise would have been taken care of by indigenous resources. Such effects analysis has pertinence when considering psychological operations, civil affairs activities, media reactions, and other components of an operation in addition to the physical infrastructure. It demands subtlety in consideration, comprehension of nuance, and a broad perspective of the operational environment.
Examples of urban critical points include traditional ones, such as command and control, reserve forces, and high ground, as well as urban-specific ones such as concentrations of noncombatants, low-density support assets (e.g., hospitals, power plants), influential civil authorities, and potable water. Additional critical points in the urban environment can include key communications nodes, influential segments of the noncombatant population, and a city's marketplace, food and fuel distribution hubs, and media representatives.
U.S. planning to oust Panamanian leader Manuel Noriega in preparation for 1989 Operation Just Cause reflected an understanding of how important identifying urban critical points could be to success. U.S. forces seized key terrain features, neutralized selected elements of the Panamanian Defense Force (PDF), and eventually captured Noriega himself. The case can be made that Noriega was the adversary's center of gravity and that particularly loyal elements of the PDF were decisive points, forces that when neutralized would lead to the toppling of the center of gravity. Other critical points included key bridges essential to cutting off PDF reinforcement of compatriot units within Panama City proper. Assuming the reverse perspective, the Americans recognized the importance of protecting U.S. servicemen's families stationed in Panama; the outcome of the campaign could have been altered significantly had the Panamanian Defense Force taken action to seize hostages or otherwise threaten family members.
By determining which elements qualify as critical points and identifying the relationships between them, the seemingly overwhelming complexity of large urban areas becomes manageable. Such points may apply to the mission immediately at hand or to another likely to be assigned in the future. There is thus a chronological element to the definition of critical points. Further, what comprises a set of critical points for an organization can change over time even if the mission remains unchanged.
There is also a conditional facet to critical point designation. Geographical, demographic, or functional elements may gain or lose critical point, center of gravity, or decisive point designation because of mission modification, a change in the environment, or actions by friendly forces, the adversary, or noncombatants. A given intersection may be noteworthy only if the enemy selects a course of action that causes the crossroads to become significant to the friendly force.
The first step in managing urban complexity, identification of points especially important to a mission, allows planners and operators to concentrate on specific elements in the urban area of operations rather than be overwhelmed by its totality. The next step involves looking at the character of these selected points in greater detail.
Taming Urban Complexity: Density
Density is the count of elements per unit of space or the quantity of activities per unit of time. While ground force leaders tend to think of density primarily in terms of area, urban operations demand they do so in terms of volume and time. A city's vertical dimension includes layer upon layer of building floors, rooftops, and subterranean passages to complement nature's ground level. It is the number of structures, firing positions, avenues of approach, enemy, noncombatants, friendly force units, key terrain, and obstacles per cubic kilometer that concern a force, as it is the number of small unit engagements, troop movements, and interactions with noncombatants per unit time within that space. As reflected in the chart on the previous page, the challenges attributable to densities, and those related to density's effects, are characteristically far greater during urban contingencies than is elsewhere the norm.
Density and critical point analyses are complementary. Density influences what qualifies for designation as a critical point: if there are many of a vital infrastructure asset, the asset may not be selected. Returning to the example of water supply, chances are that sources of usable water will not rate designation as critical points if a town has within its limits many wells with potable water. If, however, the number of water sources is low and the quantity of users is high, one or more of those sources likely will merit critical point status. Such densities can change over time. A force operating in a town with many operational wells that suffers ground contamination will find that fresh water supplies suddenly merit specification as critical points. Critical point analysis facilitates comprehension of what is otherwise overwhelmingly large and complex; density analysis further reduces the complexity by making seemingly heterogeneous challenges understandable through a common descriptive tool with application to many components of urban operations.
The 1991 assault on Vukovar, Croatia, offers an interesting study of how density can influence urban operations directly and how understanding its effects can increase a force's effectiveness. Serbian forces attacked Vukovar as part of a larger offensive seeking to void Croatia's declaration of independence. After a series of initial setbacks, Serb forces eventually surrounded the Croatian defenders within the city's confines. The attackers suffered two density-related phenomena for which they were unprepared. First, with the shrinking of the Croatian defensive perimeter, Serb forces started impeding each other's efforts. Second, Croatian counterattacks became increasingly effective. The shrinking Serb perimeter meant that they had less frontage along which to position the same number of units: the density of attackers therefore increased to a point of excess. In the case of the defending Croatians, a smaller perimeter to defend meant they could remove forces from their forward defensive lines, thereby enabling the creation of counterattack forces for which they previously lacked the force strength.
There are several ways that a force might deal with the densities it will confront during urban operations:
- Match density with density. The effects of selected densities can be neutralized by increasing the size of the force or other resources dedicated to the mission. An attacking unit could augment its strength to have sufficient men to cover every possible enemy firing position and approach route. A force with vastly superior resources not only can match an adversary's densities, but also can choose instead to overwhelm him.
- Reduce densities. Actions can be taken that have the effect of reducing the density of selected factors. The number of enemy firing positions that could threaten a friendly force might be reduced by maximizing underground and building-to-building movement; employing booby traps, chemicals, foam, or other lethal and nonlethal munitions to deny the adversary use of buildings; or planning that avoids particularly dense concentrations of windows, doorways, and other hides.
- Maintain selected densities. Isolating an adversary denies it reinforcement and resupply, thereby precluding its ability to increase desirable densities. Victory during urban contingencies often has followed successful attempts to cut off the force in a built-up area. Aachen in 1944 and Vukovar in 1991 are two examples.
- Address densities asymmetrically. There may be ways to mitigate the negative effects of particular densities without addressing them in kind. Superior discipline, training, leadership, and combined arms and joint cooperation will continue to be influential, if not decisive. Gaining the cooperation of private voluntary organizations and nongovernmental organizations can relieve units of noncombatant support tasks that deprive them of vital resources during combat operations. More active preoperation coordination with these organizations, such as inviting them to participate in training exercises and simulations, would better prepare both military and civilian agencies for operational contingencies.
- Capitalize on urban densities. Innovation may take the seemingly negative environmental factor of high densities and turn it to advantage. The density of activity in a city is a natural cloak for surreptitious actions and minor changes in routine. A friendly force commander can use this latent urban activity to aid his deceptions or shield troop movements. For example, transporting missiles on a flatbed truck is more easily concealed in a city's high-density traffic, much of it including trucks with long trailers, than on rural roads.
Seeing the City and Its Parts
The summer of 1944 confronted German General Dietrich von Choltitz with a dilemma. As military commander of greater Paris, he was to eliminate French Resistance internal to the city while simultaneously defending against approaching Allied units, missions for which he had insufficient forces. Choltitz's situation was further complicated by Hitler's demand that he destroy the city, an action the general increasingly saw as needlessly destructive (and, likely, infeasible given the resources available to him). Choltitz's seniors directed the preparation, and later the destruction, of Paris's 45 Seine River bridges. They were the only remaining crossing points over that waterway given Allied bombing of others outside the French capital. Premature destruction would trap German forces defending to their north, a second-order effect that Choltitz used to justify his disobedience of orders demanding the bridges' demolition.
The German general also recognized that some mission-critical elements were part of Paris's social rather than physical infrastructure: the leadership of the various resistance groups and the relationships between them. Choltitz understood that he lacked sufficient resources to defeat the many separate factions; he therefore chose the unorthodox (asymmetric) approach of accepting an intermediary's offer of a truce with these groups. Such an agreement provided some measure of the stability needed while Choltitz awaited promised reinforcements. Further, he realized that the resistance factions were by no means united in their goals. Communist elements sought a much different end than those looking toward a de Gaulle-led postwar government. A truce thus set the French Communists (who sought an uprising so as to legitimize their claims to power) against others trying to buy time until Allied forces arrived, forces that included Free French units supportive of de Gaulle.
Although his defense of the capital failed, Choltitz succeeded in harboring his available resources, reducing the effectiveness of the resistance organizations fighting his soldiers, and maintaining withdrawal routes for units north of the Seine. The German commander's analysis in support of these efforts was effective in part because of his insightful (1) identification of critical points that included elements of terrain, citizenry, and infrastructure, (2) understanding of the relationships between these parts, and (3) use of an asymmetric approach to address his lack of sufficient force strength to otherwise handle the densities that challenged him.
Today's leaders, military and civilian, similarly are faced with future scenarios in which there will be more in the way of urban challenges than capabilities to address them. Understanding how best to allocate resources using such concepts as critical points and density could be elemental in determining success or failure.
Dr. Russell W. Glenn is a senior analyst with RAND. His 22 years of U.S. Army service included a combat tour with the 3rd Armored Division. His is the author of Reading Athena’s Dance Card: Men against Fire in Vietnam, published by the Naval Institute Press.