Only one faith on Earth may be more messianic than Islam: multiculturalism. Without it -- without its fanatics who believe all civilizations are the same -- the engine that projects Islam into the unprotected heart of Western civilization would stall and fail. It's as simple as that. To live among the believers -- the multiculturalists -- is to watch the assault, the jihad, take place un-repulsed by our suicidal societies. These societies are not doomed to submit; rather, they are eager to do so in the name of a masochistic brand of tolerance that, short of drastic measures, is surely terminal.

I'm not talking about our soldiers, policemen, rescue workers and, now, even train conductors, who bravely and steadfastly risk their lives for civilization abroad and at home. Instead, I'm thinking about who we are as a society at this somewhat advanced stage of war. It is a strange, tentative civilization we have become, with leaders who strut their promises of "no surrender" even as they flinch at identifying the foe. Four years past 9/11, we continue to shadow-box "terror," even as we go on about "an ideology of hate." It's a script that smacks of sci-fi fantasy more than realpolitik. But our grim reality is no summer blockbuster, and there's no special-effects-enhanced plot twist that is going to thwart "terror" or "hate" in the London Underground anymore than it did on the roof of the World Trade Center. Or in the Bali nightclub. Or on the first day of school in Beslan. Or in any disco, city bus or shopping mall in Israel.

Body bags, burn masks and prosthetics are no better protections than make-believe. But these are our weapons, according to the powers that be. These, and an array of high-tech scopes and scanners designed to identify retinas and fingerprints, to detect explosives and metals -- ultimately, I presume, as we whisk through the automatic supermarket door. How strange, though, that even as we devise new ways to see inside ourselves to our most elemental components, we also prevent ourselves from looking full-face at the danger to our way of life posed by Islam.

Notice I didn't say "Islamists." Or "Islamofascists." Or "fundamentalist extremists." I've tried out such terms in the past, but I've come to find them artificial and confusing, and maybe purposefully so, because in their imprecision I think they allow us all to give a wide berth to a great problem: the gross incompatibility of Islam -- the religious force that shrinks freedom even as it "moderately" enables or "extremistly" advances jihad -- with the West. Am I right? Who's to say? The very topic of Islamization -- for that is what is at hand, and very soon in Europe -- is verboten.

A leaked British report prepared for Prime Minister Tony Blair last year warned even against "expressions of concern about Islamic fundamentalism" (another one of those amorphous terms) because "many perfectly moderate Muslims follow strict adherence to traditional Islamic teachings and are likely to perceive such expressions as a negative comment on their own approach to their faith." Much better to watch subterranean tunnels fill with charred body parts in silence. As the London Times' Simon Jenkins wrote, "The sane response to urban terrorism is to regard it as an avoidable accident."

In not discussing the roots of terror in Islam itself, in not learning about them, the multicultural clergy that shepherds our elites prevents us from having to do anything about them. This is key, because any serious action -- stopping immigration from jihad-sponsoring nations, shutting down mosques that preach violence and expelling their imams, just for starters -- means to renounce the multicultural creed. In the West, that's the greatest apostasy. And while the penalty is not death -- as it is for leaving Islam under Islamic law -- the existential crisis is to be avoided at all costs. Including extinction.

This is the lesson of the atrocities in London. It's unlikely that the 21st century will remember that this new Western crossroads for global jihad was once the home of Churchill, Piccadilly and Sherlock Holmes. Then again, who will notice? The BBC has retroactively purged its online bombing coverage of the word "terrorist"; the spokesman for the London police commissioner has declared that "Islam and terrorism simply don't go together"; and within sight of a forensics team sifting through rubble, an Anglican priest urged his flock, as The Guardian reported, to "rejoice in the capital's rich diversity of cultures, traditions, ethnic groups and faiths." Just don't, he said, "name them as Muslims." Their faith renewed, Londoners soldier on.