Finally, allied forces have announced the liberation of Mosul — now largely a ruin, reduced to penury, seething with enmity — from the Islamic State. Thousands are dead, a million displaced. Streets are still mined. And, as an Iraqi with a long career stretching from policing to governance warned me, the expulsion of ISIS has not driven the self-styled caliphate's poisonous ideology from the souls of all those left inside Iraq's second city.

The battle for Mosul is technically won. But make no mistake: America and her allies are still losing this long war against radical Islamists, who are now on pace to beat us at our own destructive game.

This war cannot be won by reducing one place to rubble. War by devastation not only breeds extremism, it requires it. At a time when so many Western elites are again so invested in weighing the merits and demerits of their own civilization, some brutal honesty is in order. If, without question, the Islamic State lowers the Muslim faith to such radical depths that its dreams of purification result in putrefaction, the West, too, must confront the way that its way of war has spread, supreme, like a virus around the world. For all the evil of fascist Germany it was the Nazi genius for slaughter that turned the West so viciously and unforgivably against itself; for all the good of the Grand Alliance, it was their still greater talent for annihilation, culminating in the atomic bomb, that won back the West for its better angels, or what was left of them.

We were warned this would happen — the evisceration of more and more frontierlands of the West. "I am not so worried about constant warring in the millennium to come between the West and non-West," Victor Davis Hanson ventured in Carnage and Culture, "if such theaters, despite the deadly gadgetry, remain outside the Western tradition and embrace different indigenous approaches to fighting … The more Western the world becomes, the more likely that all its wars will be ever more Western in nature and thus ever more deadly. We may all be Westerners in the millennium to come, and that could be a very dangerous thing indeed."

Hanson was more right than many Westerners want to believe — whether or not they countenance the existence of the West. "It is a weighty and ominous heritage that we must neither deny nor feel ashamed about," Hanson concluded, "but insist that our deadly manner of war serves, rather than buries, our civilization."

How are we doing? The American people are in broad agreement that, so far, in this now 16-year war against terrorism, in Afghanistan and Iraq, in Libya and in Yemen, and well beyond, we are faring poorly. Our skill at grand devastation is disappointing us. But we now refuse, out of a mix of principle and prudence, to win that way, the only way we trust.

We Americans have let dip the banner bearing the core principle of Western war — brutality, any measure of brutality, to the point of annihilation and crushing victory. And as we waver between disillusionment and dominance, our practices precede us, allies and enemies alike adopting our techniques, our tools, and our terrible tenacity.