Yesterday, a group of Americans larger than the number killed on Sept. 11, 2001 died.

The day before that it was the same. And the day before that. In fact, every day is 9/11 for America’s unborn children. Every day, we cleanly, efficiently, legally and privately dispatch as many children — more in fact — than Osama bin Laden had victims on that horrible day five years ago.

When we speak about “post-Christian values,” we have to remember that this dedication to the culture of death is one of them: a dedication enshrined in law in much of the West (including our own country) and surrounded by ever more draconian punishments for those who dissent. Increasingly, our culture’s devotion to abortion, homosexual “marriage,” blasphemy, the harvesting of dead babies for body parts, and the stampede to kill the weak and old is becoming a central component of why we fight.

More and more, the struggle of the West with radical Islam looks like a battle, not between good guys and bad guys, but between pagan Rome and pagan Carthage.

When I point this out, some people ask me if I’m saying that since Western culture is depraved, we have no right to fight radical Islam.

No. I do not say we are too morally bankrupt to fight radical Islam. I say we are too morally bankrupt to trust that our opposition to radical Islam makes us trustworthy.

I say that Christians, in particular, have to remember  that though we are obliged to the duty of patriotism (which is, after all simply another way of saying we are obliged to love our neighbor), it does not follow that we are obliged to love our neighbor more than God. When our neighbor tries to get us to defend his sinful acts because they aren’t as nasty as somebody else’s sinful acts, we have a duty to tell him he’s wrong.

The older I get, the more incorrigibly Catholic my outlook gets. I regard the great struggles of our time through the lens of Ephesians 6:12 and following. I do not believe flesh and blood is our ultimate enemy. I also do not believe flesh and blood is our ultimate friend. I think the projects of demonizing our enemies and the project of making the post-Christian secular West the highest good are both riddled with folly. Our enemies think they are fighting a holy war. But not a few in the West are promising a secular messianic vision of a world made happy through democracy and capitalism unfettered from the Christian tradition that gave rise to them.

Christians have to be very careful in how they respond to that, because the easy temptation, in our revulsion at the brutality and evil of Radical Islam, is to simply baptize whatever the post-Christian West wants to do in response.

Christians must indeed fight a holy war. But that means they must pay attention to St. Paul, who tells us that the weapons of our warfare are primarily spiritual and are ordered toward Christ, not toward earthly power and domination. Therefore, we Christians cannot just fight against radical Islam (which is but one of the enemies of Christ).

We must also fight against post-Christian secularism that hates Christ just as much as radical Islam. And we must supremely fight against the sin in the Church (and in our own hearts) that always tempts us to say, “I thank you O Lord, that I am not like other men.”

Yes, sometimes literal arms are necessary in this world. But without the spiritual arms, we are fighting in vain. Indeed, we are fighting against Christ.

The temptation of this world is always to lure us to the siren song of believing that we can make this world enough: that one of our little systems of order can stand in for heaven. And one of the best tricks the devil has in his little bag is the trick of sending evils into the world in pairs.

That way, he can inflame our hatred of one evil and stampede us into the defense of the opposite evil. The sensible path through all this is to follow Christ, not the winds of this world. For the reality is that a diseased and inflamed spirituality like radical Islam cannot be cured by a diseased and flaccid spirituality like post-Christian secularism and the New Age goo of the West.

Only a healthy spirituality can cure what ails both East and West: and that means the fullness of the Catholic faith.

On the whole, I’m glad pagan Rome defeated pagan Carthage. Rome was about the best there was in paganism. But the very best of paganism still was incapable of looking God in the eye without saying, “Crucify him.”

We Christians will have to remember that, both when radical Islam threatens to kill us and when Caesar seeks to co-opt us.

Mark Shea is senior content editor

for CatholicExchange.com.