Design for a 15,000-person UN Legion

Project on Defense Alternatives Carl Conetta and Charles Knight October 1995

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Preface

This design for a UN legion was commissioned by Dr. Carl Kaysen, Chairperson of the Committee on International Security at the American Academy of Arts and Sciences for inclusion as an appendix in their report, Appendix: Design for a Streamlined UN Legion in Carl Kaysen and George Rathjens, Peace Operations by the United Nations: The Case for a Volunteer UN Military Force. It is a scaled-down version of the UN legion proposed in Vital Force..

Strategic and Operational Factors Relevant to Force Design

Several aspects of peace operations are especially relevant to the design of a UN force. First, these operations often emphasize activities that are ancillary to the main functions of a fighting force -- for instance, humanitarian relief and national reconstruction. Hence, a UN force should possess a higher proportion of units suited to these tasks, such as civil affairs and engineering units, than would a pure warfighting force. Second, peace operations will often require field units to exercise influence over a larger area than would be standard for units of a comparable size in war. This implies greater independence, initiative, flexibility, and skill at lower levels of organization.

Turning to the issue of combat capability: although peace operations would not require a field force to engage in full-fledged warfighting -- distinguished by wide-ranging and protracted offensive and defensive operations -- missions often will involve intermittent combat. Where local consent to a UN mission is unstable or uneven, some of the activities of the field force, such as controlling the movement of belligerents, may prompt an aggressive response. Challenges to the force may focus on the small-unit level, reflecting the poor discipline and weak command and control of belligerent armies. The force also may have to protect sites, areas, convoys, and UN-mandated activities against raids, and to conduct humanitarian relief and reconstruction efforts while under imminent threat of attack. In some cases, effective protection may require small-scale counter-attacks, punitive raids, or rescue missions.

The greatest challenge to the force would come should a capable belligerent decide to launch a concerted offensive against it -- in essence declaring war on the UN force and its mission. In such cases the entire operation might have to be redefined, and this could involve the reinforcement, relief, or withdrawal of the field force. This, of course, implies that the field force is sufficiently capable either to hold its own while awaiting relief or to conduct a fighting withdrawal.

This brief overview of possible field activities and combat situations suggests that a UN field force not be uniform in design -- that is, dominated by any one type of combat unit. Infantry on foot, for instance, have a critical role to play -- but so do engineers, highly-mobile reconnaissance units, and a variety of troops under armor. The review also suggests that the subunits of the field force -- battalions and companies -- should have greater mobility, protection, and firepower on average than is typical for the regular and light infantry forces that often undertake peacekeeping. Indeed, given the low ratio of force to space typical of peace operations, the capacity of the field force to perform its mission safely depends on most of its units having some form of transport close at hand.

The legion's strategic utility will depend not only on what it can do once it has deployed, but also on how fast it can deploy. Indeed, the possibility of decisively influencing the course of mid-level contingencies with a force of 5,000 soldiers rests principally on the prospect of inserting it at the right time. Thus, the capacity of the force to perform the critical functions of compellance, deterrence, and reassurance depends on the balance it strikes between combat capability and deployability. This criteria favors a "middle-weight" force design, such as the one that guided the development of the US Army's High-Technology Motorized Infantry Division in the 1980s or, more recently, has found expression in the renovation of the US Second Armored Cavalry Regiment.

Given the wide variety of tasks and functions that a UN Legion would have to undertake, "modularization" would be another distinguishing feature of an appropriate design. Achieving a balance between capability and deployability will depend on deploying what is needed for each specific operation, and not much more. This implies that a variety of smaller functional units -- in this case, companies -- exists independently, and that brigade headquarters be sufficiently large to incorporate and oversee them effectively.

Several other factors also favor a larger-than-usual brigade headquarters. First, the headquarters may often have to lead or cooperate closely with national military contingents and civilian organizations. Second, it may have to provide a stable basis for "relief in place" by larger, follow-on forces. And, finally, the brigade headquarters may have to "spin-off" streamlined replicas of itself to lead smaller missions or assist in the training of national contingents -- and do so without substantially compromising its ability to respond to larger contingencies.

Force Structure for a UN Legion

The following force structure design is an example of one that conforms to the requirements set out in the previous section. In this model, developed by Carl Conetta and Charles Knight of the Project on Defense Alternatives at the Commonwealth Institute, a UN legion of 15,000 troops would comprise:

• 2 Brigade HQs (340 staff and support personnel each)
• 2 Motorized infantry battalions
• 2 Light mechanized Infantry battalions
• 1 Cavalry squadron
• 1 Light armored cavalry squadron (37 light tanks)
• 2 Armed Scout helicopter companies (18 aircraft each)
• 4 Field artillery batteries (eight guns each)
• 2 air defense companies (12 mounted air defense systems each)
• 2 Combat engineer companies
• 2 Signal companies
• 2 Field intelligence companies
• 2 MP companies
• 2 Civil affairs companies
• 2 Field Logistics Bases

Each of the brigade headquarters -- in effect, field headquarters -- would have 300 officers and enlisted personnel serving in command positions or in a headquarters company. The headquarters would be designed to facilitate expansion, if needed, or to permit a smaller, free-standing section to be detached to oversee or reinforce smaller operations or to assist in the training of national peacekeeping contingents.

Directly reporting to each headquarters would be one each of signal, field intelligence, military police, and civil affairs companies. Together these companies would add 600 personnel. Directly servicing these companies and the headquarters would be more than 100 logistics personnel. The proposed model makes provision for two such clusters of brigade/field headquarters and associated companies.

Turning to the main tactical units: The model includes two each of motorized infantry and light mechanized infantry battalions and one each of cavalry and light armored cavalry. Both types of infantry battalions would have three line companies and one fire support company as well as headquarters elements. The two would differ in that the motorized infantry would ride in unarmored trucks kept at the company level, while the light mechanized infantry would ride in light APCs, such as the USMC's Light Armored Vehicle. Notably, however, all infantry keep some mode of transport close at hand.

The model also provides for two types of cavalry. The first would ride on lightly armored jeeps or small reconnaissance vehicles. These would be well-suited to observation, monitoring, and light escort duty. The second type -- light armored cavalry -- would ride on larger, better protected vehicles and would include light tanks (37 to the squadron) among their organic weapon systems. These somewhat heavier cavalry units -- still quite light when compared with America's older armored cavalry squadrons -- would be suited to use as a screening or even a light counter-attack element.

Unlike the infantry battalions, both types of cavalry units would have four line companies (called "troops"). In addition, the cavalry would have two mortar platoons; the light armored cavalry, a full mortar company with four platoons. These arrangements allow the cavalry troops to operate in pairs, as is customary, and also give the legion's commander greater freedom to deploy half a cavalry squadron (two line companies plus mortar platoons) while holding the other half in strategic reserve.

Finally, the legion would incorporate several types of smaller, supporting units: four companies of light field artillery and two companies each of armed scout helicopters, combat engineers, and air defense artillery. (Aviation companies, with a mix of scout helicopters and light observation planes, could substitute for the proposed pure helicopter companies.) The combat engineer company would be well-equipped and large as such units go, with at least 200 combat and 40 service support personnel.

Considered as a whole, the legion is easily divisible into two identical halves -- so that one can deploy to the field while the other serves as a strategic reserve and rotation base. The principal tactical units -- infantry and cavalry -- can also be divided along another axis into two segments, one somewhat heavier than the other. On the light side are the motorized infantry and regular cavalry units; on the heavier side (actually, "middle-weight") are the light mechanized infantry and light armored cavalry. Having two types of infantry and cavalry allows for a more precise tailoring of deployment packages. This is key to achieving an economy of force which, in turn, serves the goal of rapid deployment. Force packages can be fine-tuned further by the addition of supporting companies: air defense, artillery, combat engineers, etc.

Some Typical Deployment "Packages"

A force tailored to perform a mission of ceasefire monitoring might involve two motorized infantry companies, two cavalry troops, a scout helicopter company, and one company each of signal and field intelligence personnel. A more demanding mission would be the provision of humanitarian relief and support for national reconstruction under conditions of low but tangible threat. This would require a larger and somewhat more robust force package, for instance:

• one motorized infantry battalion, including a fire support company
• two troops of cavalry, each supported by a mobile mortar platoon, and
• one each of armed scout helicopter, combat engineer, military police, civil affairs, signal, and fieldintelligence companies.

Most demanding would be a mission involving the protection of safe areas and the disarmament of factions. For such a mission, planners might add to the package just described a light mechanized infantry battalion, two light armored cavalry troops, two artillery batteries, and one air defense company. With these additions and service support elements, the package would constitute a 5000-person reinforced brigade. Among its assets would be 18 light tanks, 16 155-mm field pieces, 33 medium-heavy mortars, 12 mobile air defense systems, 18 armed scout helicopters, and approximately 200 other combat vehicles mounting a variety of weapons.

These hypothetical deployment packages serve to illustrate the range of missions that the proposed force could undertake. Naturally, the capacity of the legion to meet the requirements of any specific operation would depend heavily on the operation's scope, the level of hostility in the theater, and the size and capability of potential belligerent forces. Nonetheless, the proposed legion is large and varied enough to deploy any one of the packages described above while retaining a duplicate package at home as a strategic reserve. Furthermore, even the least combat capable of these hypothetical packages would have a significantly greater operational mobility and capacity for self-protection than would comparably-sized light infantry forces of the type often used in peacekeeping operations.

Capacity for Rapid Deployment

A judicious choice of equipment should allow the proposed structure to balance effectively the requirements of rapid deployment, security, and combat capability. Assuming that the legion's heaviest assets, its APCs and light tanks, weigh between 16 tons (APCs) and 25 tons (light tanks), it should be able to deploy the lead element of a brigade -- a reinforced light mechanized infantry battalion -- in approximately 100 C-141 sorties. The entire brigade, including all support and service support elements, should be able to deploy in less than 500 C-141 sorties. This means that, drawing on a fleet of only 36 C-141s (or its equivalent), the lead battalion could deploy in three or four days to a site 5,000 miles from its home base. Within twelve days, all of the brigade's combat elements would be able to deploy.

Field Logistics Organization

Every tactical unit would incorporate some organic service support. In addition, the legion would have two independent field support units, called Field Logistics Bases. Each of these would have 1000 personnel distributed among a company-sized headquarters and subunits for port and depot control, tactical ground and air transport, supply, equipment recovery and maintenance, and medical and personnel services. Each of the field bases would have at its disposal at least 18 utility helicopters, which could be used to ferry troops, and 300 ground vehicles including cargo trucks, tankers, repair and recovery vehicles, and ambulances.

Personnel

The legion as a whole would comprise 15,000 officers and troops. Tactical units would incorporate about 6,700 combat personnel and approximately 1,400 organic support personnel. The two Field Logistics Base organizations would add another 2,000 personnel. Augmenting the primary personnel would be 500 replacements. Hence, the total number of deployable personnel would be approximately 10,600 -- although no more than about 5,000 would be in the field at any one time.

Rounding out the legion would be approximately 1,800 trainees, 400 trainers, 800 central staff personnel, and 1,400 base support and central logistics personnel. The central staff personnel would be distributed among various functions: planning and operations, intelligence, logistics, acquisition, doctrine and training, personnel, administration, and financial management. Base support personnel would provide essential services for the legion's base and training areas. Central logistics personnel would staff the legion's "home base" depots, repair shops, and medical facilities.

Appendix

1) Personnel Allotment for a 15,000-person UN Legion

2) Description of Tactical Units

Brigade/Field headquarters. 300 staff and tactical personnel, 40 support personnel. Organic subunits include security, reconnaissance, and special operations platoons.

Motorized Infantry battalion. 690 combat troops, 100 support troops.

• 1 Headquarters and HQ Company (includes security and reconnaissance platoons)
• 3 motorized infantry companies (unarmored trucks)
• 1 fire support company. Each has:
  • 1 fire support platoon (vehicle-mounted automatic cannon)
  • 3 mortar platoons (3 vehicle-mounted 107-mm mortars each)

Light Mechanized Infantry battalion. 675 combat troops, 135 support.

• 1 HHC (includes security and reconnaissance platoons)
• 3 light mechanized infantry companies
• 1 mortar company (12 vehicle-mounted 107-mm mortars)

Cavalry squadron. 375 combat troops, 80 support troops.

• 1 HHC (includes security platoon)
• 4 scout troops
• 2 mortar platoons

Light Armored Cavalry squadron. 550 combat troops, 135 support troops.

• 1 HHC (includes security platoon)
• 1 mortar company
• 4 troops. Each has: 2 scout platoons and 2 armor platoons.

Armed Scout Helicopter company. 18 helicopters, 100 combat troops, 60 support troops.

Independent companies and batteries:

Air defense battery. 12 air defense systems, 120 combat troops, 25 support troops.

Combat engineer company. 200 combat troops, 40 support troops.

Signal company. 120 combat troops, 15 support troops.

Field intelligence company. 150 combat troops, 20 support troops.

Military police company. 130 combat troops, 15 support troops.

Civil affairs company. 150 combat troops, 75 support troops.

3) Combat and Support Units and Personnel

4) Table of Equipment (partial)

5) Costs Estimates for a 15,000-person UN Legion

Estimate of initial capital expense does not include any discount for equipment purchases, although substantial savings should be possible. Also, it does include substantial expenditures for base renovation, which may not be necessary, and expenditures for constitution of a 90-day operational reserve stockpile, which could be reduced to two months. Thus, the estimate is a high-end one; it may be possible to bring it down to $1.3 billion.

This initial expenditure will occur over a 30-month period. During this period, the personnel and O&M portions of the budget will be much less than estimated in the "Stable Annual Budget." Overall, I estimate the 30-month budget for the development period to be $1 billion in addition to initial capital outlays. Hence, the development period would require a total expenditure of approximately $2.6 billion (or less) over 30 months. During this period there would be little or no incremental expenses -- because there would be little or no field activity, other than training, which is already reflected in the annual budget.

a) Initial Capital Expenses: 1.568 billion

This cost includes the procurement cost of all equipment for field, base, and office use. It also includes the estimated cost of substantial base renovation. Finally, it allows for the constitution of a 90-day operational reserve stock of food, POL, ammunition, spare parts, and other consumables. There may be a variety of opportunities to realize substantial savings (on the order of $300 million.) However, these are not taken into account here. Potential savings could be realized through (i) discounted purchase of equipment, (ii) a lower than estimated need for base renovation, and (iii) a smaller operational reserve stock. Initial capital costs are divided into three categories: equipment purchase; base renovation and construction; and constitution of an operations stockpile.

b) Stable, long-term average annual budget.

This budget applies to period beginning three years after the completion of a 30-month development phase.

c) Incremental costs associated with field operations.

These estimates are for one year of full utilization -- that is, 5,000 troops in the field continuously. Please note that the costs of strategic lift are included, assuming two separate deployments. In each case about 50-60 percent of the force is deployed by air.

Citation: Carl Conetta and Charles Knight, Design for a 15,000-person UN Legion, Project on Defense Alternatives. Cambridge, MA: Commonwealth Institute, October 1995.
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