There are two schools of thought here: Trump’s view, which, if it’s not quite “boys will be boys,” is understanding and in large measure indulgent, and a kind of fastidiousness that goes in the other direction altogether. In February 2005, then-three-star General Jim Mattis said, “You go into Afghanistan, you got guys who slap women around for five years because they didn’t wear a veil. You know, guys like that ain’t got no manhood left anyway. So it’s a hell of a lot of fun to shoot them.” There was a fuss, and he got a reprimand for not choosing his words more carefully. It probably would have been worse for him in Barack Obama’s administration than it was in George W. Bush’s.

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The truth about Mattis, of course, is that in practice he believes in erring on the side of restraint, cautioning his marines not to take a shot when civilians are likely to get hit, and gently talking a newly elected Trump out of his belief in the utility of torture. But his unvarnished remarks, like my juvenile T-shirt (complete with a skull with a red star on its forehead, as I remember), indicate the dangerous lines up to which militaries must go, but across which they must not pass.

War, and close combat above all, requires the desire to destroy the enemy, and destruction here is all about shredding human bodies with bombs, bullets, and, even in this day and age, edged weapons. It is about killing. Decent people recoil from it; a liberal society, even one accustomed to gun violence on a large scale, will often try to avoid it, but there it is. And to build the necessary aggression, things have to be different in war than in peace, and soldiers have to have their blood up.

As ever, Shakespeare can guide us through this. In Henry V, the bard’s perfect king masses his troops before the French city of Harfleur, and as he leads them “once more unto the breach,” he says:

In peace there’s nothing so becomes a man As modest stillness and humility; But when the blast of war blows in our ears, Then imitate the action of the tiger Stiffen the sinews, conjure up the blood Disguise fair nature with hard-favored rage.

And so soldiers do. Henry rouses them by appealing to their pride, their lineage, their patriotism, and their prowess. He will lead them in person; he is the noble warrior even if he is not fighting for a noble cause.

But it does not end there, because the city is not taken by that assault. Instead, Henry delivers a terrifying speech to the governor of Harfleur and his people, telling them what will befall them if they do not surrender on the spot:

The gates of mercy shall be all shut up, And the fleshed soldier, rough and hard of heart, In liberty of bloody hand shall range With conscience wide as hell, mowing like grass Your fresh fair virgins and your flow’ring infants.

He lays it on thick, returning to the theme of rape, describing what it will be like when “your pure maidens fall into the hand / Of hot and forcing violation.”