The above graphic from CNN illustrates an interesting point: “it isn’t the size of the man in the fight, but the size of the fight in the man.”
Even with solid support from artillery and bombing, and a vast (but largely green) army of uncertain loyalty, grinding down ISIS is going to take some time. I’m used to 5:1 or 10:1 ratios to gain a victory in the field, but 21:1?
And then, there is that 500 US contingent opposing ISIS. Not even 0.5% of that fighting force, but how much effective firepower, how much weight do they bring down to the battlefield on behalf of the good guys? Five percent of the total army? Maybe 20%?