This post from Belmont Club and the WaPo article it links to are some of the most moving, complete pictures of war at the small scale that I've come across in a while.  Wretchard describes how the in-your-face, can't blink attitude adopted by the soldier profiled -

..gives you an idea of the irreducibly violent nature of the job. The one psychological thing about the US presence in Mosul, which Ruiz exploits to effect, is the now accepted notion that they will stay until the insurgency is beaten. He uses it to drive the enemy not simply from the physical buildings of Mosul but from the mental landscape of the residents. Imperceptibly but steadily, the US military has come to intuitively understand the key features of human terrain. Although writers will attempt to capture that knowledge in field manuals and instructional material, its living repository is really in the memories and experience of men like Sgt. Ruiz.

To some extent, one can sympathize with pacifists who fear the very existence of that knowledge, who would prefer a world innocent of the craft of war. The structure of armies are themselves testaments to the destructiveness of what they must contain. The emphasis on discipline; the focus on control; even ceremony, are ways of keeping the lid on a genie which it is perilous even to regard. Armies parade to music so that we can forget what they are for.

A money quote from Ruiz which captures both the Hobbesian, animalistic simplicity of the situation and simultaneously hints that he's aware of what my San Francisco colleagues find appalling -

Sgt. 1st Class Domingo Ruiz, on patrol in Mosul with the unit he leads, was once a gang member in Brooklyn. He says the rules of the street also apply in Mosul. "What I see here, I saw a long time ago," he said. "It's the same patterns."

It's simply tragic that men like Sgt Ruiz are, in so many ways, destined to be cursed in polite, liberal society as, well, members of yet another gang.   As Wretchard notes, his presence is neither merely physical nor mental.   Rather, it's a potent mix of value driving determination driving physicality.  Any one of these steps alone is so often the target of cynicism and scorn amongst post-modern society.  Our bien-pensants draw a laughably quick line from values that dominate Ruiz's life like Honor, Duty to cartoonish 3rd Reich-inspired effigies.  Individual determination is too often dismissed as subject to the whims of social pressures writ large and the disenfranchised.   And physicality - brutish and that which corrupts.

And, alas, it's precisely Ruiz's linking of these forces that shields the gentry from recognizing what actually holds up the wall separating them from the barbarians.  When men like Ruiz do their jobs too well Lee Harris' Forgetfulness sets in --

Forgetfulness occurs when those who have been long inured to civilized order can no longer remember a time in which they had to wonder whether their crops would grow to maturity without being stolen or their children sold into slavery by a victorious foe....

They forget that in time of danger, in the face of the enemy, they must trust and confide in each other, or perish....

They forget, in short, that there has ever been a category of human experience called the enemy. "That, before 9/11, was what had happened to us. The very concept of the enemy had been banished from our moral and political vocabulary. An enemy was just a friend we hadn't done enough for yet. Or perhaps there had been a misunderstanding, or an oversight on our part--something that we could correct....

"Our first task is therefore to try to grasp what the concept of the enemy really means. The enemy is someone who is willing to die in order to kill you. And while it is true that the enemy always hates us for a reason, it is his reason, and not ours."

First the sheep question the need for sheep dogs like Ruiz.  Later, in the more virulent San Francisco form, they begin to hate and resent them not merely as a symbol, but, in their own contorted minds, as the cause of the darkness they wish to deny in men's souls.  They merely see one street gang -- with more expensive weapons -- battling another and scream "not in our name."  Ruiz sees far more.