[John] Nagl’s rule of thumb, the one found in the [US Army] counterinsurgency manual, calls for at least a 1-to-50 ratio of security forces to civilians in contested areas. Applied to Afghanistan, which has both a bigger population (32 million) and a larger land mass (647,500 square miles) than Iraq, that gets you to some large numbers fast. Right now, the United States and its allies have some 65,000 troops in Afghanistan, as compared to about 140,000 in Iraq. By Nagl’s ratio, Afghanistan’s population calls for more than 600,000 security forces. Even adjusting for the relative stability of large swaths of the country, the ideal number could still total around 300,000–more than a quadrupling of current troop levels. Eventually, Afghanistan’s national army could shoulder most of that burden. But, right now, those forces number a ragtag 60,000, a figure Nagl believes will need to at least double and maybe triple. Standing up a force of that size, as the example of Iraq has shown us, will take several years and consume billions of U.S. dollars.
And that’s just the Leviathan side of Barnett’s duo–this excludes the entire other army (on top of the 600,000) of engineers, aid workers, construction project leaders, humanitarian/conflict negotatiators, reconstruction crews, etc. I have a hard time seeing how this happens.