10,000 Won’t Do It: The Mathematics of an American Deployment to Fight ISIL


Since followers of the self-proclaimed Islamic State in Iraq and the Levant (ISIL) have launched a succession of attacks in Paris, Sen Bernardino, Indonesia, and elsewhere, we have been inundated with another wave of recommendations on how to fight this group.  Distinguished senators and retired generals, along with security and terrorism experts, are saying the United States must commit ground forces into the fray.

Senator John McCain “wants 10,000 U.S. ground troops in Syria to crush the Islamic State — and blames President Barack Obama’s lack of leadership and strategy for the “phenomena of ISIS.”  McCain, who has some experience at war, wants action now and is of course also seeking political advantage in attacking the current administration.  In a recent interview retired Marine General Anthony Zinni also called for immediate action.  He repeated the call for 10,000 troops to be deployed.  Zinni said, “Limited airstrikes against [Islamic State] targets are not enough,” but “Two brigades would take ISIS out of Iraq in a heartbeat.”  According to Zinni: “You cannot control people and ground without ground forces.”  Even before Paris there were calls for such action.

On November 14, 2014, Max Boot of the Council on Foreign Relations presented Policy Innovation Memorandum 51, “Defeating ISIS.”  In this memorandum Boot calls for increasing the size of the U.S. force presently in Kuwait and Iraq, citing estimates of the force size required from 10,000 (General Zinni) to 25,000 (Kim and Fred Kagan).

Although committing more troops seems unlikely now (the United States currently has approximately 3500 troops in Iraq and special operations forces in Syria) it is worth delving a bit deeper into the numbers being thrown about.  While I did not command above the battalion level and retired as a colonel, I served as a planner for the bulk of my active duty career upon graduation from the School of Advanced Military Studies.  In 2002, I arrived at Third U.S. Army for duty as the Deputy Chief of Staff, J5 — the lead planner for the Combined Forces Land Component Command.  This command was responsible for developing the plans for and conducting the land invasion of Iraq in 2003.  As a part of this job, we were responsible for developing and presenting plans which matched the reality, as we saw it, of the actual situation we would face on the ground during the invasion.  From hard-earned experience, I realized pretty quickly that policymakers are enamored by numbers, and when it comes to troop numbers, the smaller the better.

One of my first experiences in 2002 took place when we were asked to answer a question from the Office of the Secretary of Defense (OSD).  Our policy guidance for the conclusion of the operation was a stable Iraq with its territorial integrity intact, as well as a broad-based government that renounces WMD development and use, support for terrorism, and threatening its neighbors.  At the time, I thought perhaps answering the question would entail how we were translating policy guidance into attainable operational and tactical tasks.  How silly of me.  Instead the question meant, “We have a brigade on the ground.  Why can’t we go now?”  At the time we were asked this question, there was one U.S. Army armored brigade in Kuwait and a very senior person in OSD wanted to know why we could not begin the invasion with this single brigade, immediately.

We settled on answering the note from OSD with the mathematics of war.  The conduct of war requires the expenditure of materiel.  Fuel, water, food, and ammunition are among many items consumed in the execution of operations.  Items expended and used require replacement.  Replacement requires transport over some distance from a warehouse in the United States to the point of need in the theater of war.  Some call this the “tooth to tail” ratio, but this is too simplistic.  The mathematics of war encompasses all the work required to sequence and sustain the battles and engagements which are the result of a major campaign.  This is especially true when we are projecting power in the form of Army units from the United States to another country — in this case, Iraq.  This is why there is truth to the adage, “Amateurs talk tactics and professionals study logistics.”

So, to answer the OSD question we calculated what it would take to move one M1A1 tank, with a crew of four, from a base camp in Kuwait to Baghdad, Iraq.  A tank consumes W gallons of fuel and expends X number of tank cannon and machine gun rounds against light to moderate resistance.  The crew of four requires Y pounds of rations and Z gallons of water per day over an assumed duration of A days.  The tank can carry some of these supplies, with the battalion support platoon carrying the remainder.  To resupply the support platoon requires B number of additional trucks.  To maintain and sustain B numbers of trucks requires C number of mechanics.  If there are wounded, the brigade requires medical supplies and aero-medevac helicopters.  The list went on.  People who blithely throw about the figure 10,000 soldiers are not paying attention to the mathematics of war.  The mathematics of war is compounded by the distance the force and sustaining materiel must travel.

In the case of a campaign against ISIL, the length of the lines of communication in this theater of war, from seaports and airports to key ISIL-held cities, is daunting. From our bases in Kuwait, it is roughly 1,000 kilometers to Mosul.  To Raqqa it is another 400 kilometers.  If we were to attack ISIL through the Syrian port of Latakia, the distance to Raqqa is 300 kilometers.  We can assume these lines of communication will be contested.   It may well only require two U.S. brigade combat teams, along with French, Russian, Turkish, Kurdish, Jordanian, and Iraqi forces to defeat ISIL in combat.  Nonetheless, it will take a lot more than 10,000 soldiers to deliver two brigade combat teams to Mosul and Raqqa in the form required to engage in battle with an enemy who clearly knows how to fight.

We professionals know this because we know the mathematics of war.  We cannot forage our way to Mosul and Raqqa.  Fighting and defeating ISIL in Mosul and Raqqa is also not the end of the required action.  As Boot pointed out in his Policy Innovation Memorandum, a strategy to defeat ISIL requires the United States to “[p]repare now for nation building.”

The mathematics of war also considers the “troop-to-task” ratio.  In order to establish conditions of security such that the range of U.N. agencies, private and non-governmental organizations, and even Iraqi and Syrian national agencies will restore life-sustaining functions to towns and cities, a strategy has to include forces for, as Boot pointed out, “nation building” or “re-building.”

This is not blind obedience to the Powell doctrine of overwhelming force.  Our military advice needs to take into account what it takes to go to the war, fight and win the war, sustain the war, and settle the war enough to handover to a transition force.  If we are just conducting a punitive expedition, this is another case entirely.  We can then just execute the punitive action, withdraw the force and return home.

Highlighting this need for clearly stated military advice is this example drawn from former Secretary of Defense Robert Gates’ memoir Duty. Military advice must take into account the problems which stem from a different baseline knowledge of military matters between military professionals and policymakers.  Gates cites an incident that occurred during the summer of 2009 when he debated President Obama on troop numbers for the Afghan surge. This disagreement was driven in part by a lack of understanding of what the range of numbers included. When Secretary Gates explained that the military had assumed that the 5,000 “enablers” would be in addition to combat troops and were not part of the additional 21,000 troops that the military had requested, President Obama angrily asserted that this was “mission creep” and that the public and Congress would not differentiate among types of troops and only look at final numbers deployed. In this instance professional officers were incorrect in assuming, on behalf of some of their civilian leaders, a depth of understanding of the mathematics of war.   

Military and security professionals need to overcome policymakers’ fascination with low numbers of troops being the best course of action and their resultant tendency to micro-manage troop numbers down to the tactical level.  Military advice must be solid, fact-based advice on the structure we would need to put into place to truly defeat ISIL on its home turf.  After 14 years at war, we know no plan can look with certainty beyond initial contact with the enemy main body — the enemy gets a vote.  We know friction and the fog of battle are real.  Still, unsubstantiated numbers proposed through the media and other journals do not really help address the issue at hand.  Frankly, Sen. McCain and Gen. Zinni ought to realize that what they are saying about what it would take to defeat ISIL is not helpful in crafting the plans really needed to accomplish this task.  Hurling low ball figures without considering the mathematics of war is not rendering sound military advice, it is chasing sound bites and re-tweets.


Kevin C.M. Benson, Ph.D. retired from active duty in the Army as a colonel after 30 years of service.  He commanded tank and cavalry units and also served as a general staff officer at corps, joint task force and land component command levels.  He writes for professional journals and has the privilege of teaching.  He lives in Lansing, KS.

Photo credit: Staff Sgt. Jennifer Bunn, U.S. Army

Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; bingbot/2.0; +http://www.bing.com/bingbot.htm) Chrome/116.0.1938.76 Safari/537.36