Both Chris and I questioned the proposed force size figures being bandied about by advocates and opponents of a U.S. ground force intervention to combat Daesh in Iraq and Syria. It turns out that we were not the only ones who found these figures to be curious. Kevin Benson, a retired U.S. Army colonel and the Deputy Chief of Staff, J-5 for the Army component of U.S. Central Command in 2002, found these proposed force levels to be far too low on simple logistical grounds. In an analysis published on War on the Rocks, he summarized the challenges and requirements:
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.
Two BCTs would be a minimum force level commitment just to defeat Daesh on the battlefield. They would clearly be insufficient for follow-on stability or counterinsurgency operations.
Benson concludes with an excellent point about the pitfalls of spitballing numbers in policy discussions:
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.
