There is here a question of what we mean when we speak of things like Christianity, Islam and secularism. There are more than a billion Christians and more than a billion Muslims and uncountable secularists who mix all things. It is difficult to decide what you mean when you say any of these words and easy to claim that anyone else's meaning is (or is not) the right one. There is a built-in indeterminacy in our use of language that allows us to shift responsibility for actions in Paris away from a religion to a minor strand in a religion, or to the actions of only those who pulled the trigger. This is the universal problem of secularism, which eschews stereotyping. It leaves unclear who is to be held responsible for what. By devolving all responsibility on the individual, secularism tends to absolve nations and religions from responsibility.

This is not necessarily wrong, but it creates a tremendous practical problem. If no one but the gunmen and their immediate supporters are responsible for the action, and all others who share their faith are guiltless, you have made a defensible moral judgment. But as a practical matter, you have paralyzed your ability to defend yourselves. It is impossible to defend against random violence and impermissible to impose collective responsibility. As Europe has been for so long, its moral complexity has posed for it a problem it cannot easily solve. Not all Muslims — not even most Muslims — are responsible for this. But all who committed these acts were Muslims claiming to speak for Muslims. One might say this is a Muslim problem and then hold the Muslims responsible for solving it. But what happens if they don't? And so the moral debate spins endlessly.

This dilemma is compounded by Europe's hidden secret: The Europeans do not see Muslims from North Africa or Turkey as Europeans, nor do they intend to allow them to be Europeans. The European solution to their isolation is the concept of multiculturalism — on the surface a most liberal notion, and in practice, a movement for both cultural fragmentation and ghettoization. But behind this there is another problem, and it is also geopolitical. I say in Flashpoints that:

Multiculturalism and the entire immigrant enterprise faced another challenge. Europe was crowded. Unlike the United States, it didn't have the room to incorporate millions of immigrants — certainly not on a permanent basis. Even with population numbers slowly declining, the increase in population, particularly in the more populous countries, was difficult to manage. The doctrine of multiculturalism naturally encouraged a degree of separatism. Culture implies a desire to live with your own people. Given the economic status of immigrants the world over, the inevitable exclusion that is perhaps unintentionally incorporated in multiculturalism and the desire of like to live with like, the Muslims found themselves living in extraordinarily crowded and squalid conditions. All around Paris there are high-rise apartment buildings housing and separating Muslims from the French, who live elsewhere.

These killings have nothing to do with poverty, of course. Newly arrived immigrants are always poor. That's why they immigrate. And until they learn the language and customs of their new homes, they are always ghettoized and alien. It is the next generation that flows into the dominant culture. But the dirty secret of multiculturalism was that its consequence was to perpetuate Muslim isolation. And it was not the intention of Muslims to become Europeans, even if they could. They came to make money, not become French. The shallowness of the European postwar values system thereby becomes the horror show that occurred in Paris last week.

The Role of Ideology

But while the Europeans have particular issues with Islam, and have had them for more than 1,000 years, there is a more generalizable problem. Christianity has been sapped of its evangelical zeal and no longer uses the sword to kill and convert its enemies. At least parts of Islam retain that zeal. And saying that not all Muslims share this vision does not solve the problem. Enough Muslims share that fervency to endanger the lives of those they despise, and this tendency toward violence cannot be tolerated by either their Western targets or by Muslims who refuse to subscribe to a jihadist ideology. And there is no way to distinguish those who might kill from those who won't. The Muslim community might be able to make this distinction, but a 25-year-old European or American policeman cannot. And the Muslims either can't or won't police themselves. Therefore, we are left in a state of war. French Prime Minister Manuel Valls has called this a war on radical Islam. If only they wore uniforms or bore distinctive birthmarks, then fighting only the radical Islamists would not be a problem. But Valls' distinctions notwithstanding, the world can either accept periodic attacks, or see the entire Muslim community as a potential threat until proven otherwise. These are terrible choices, but history is filled with them. Calling for a war on radical Islamists is like calling for war on the followers of Jean-Paul Sartre. Exactly what do they look like?

The European inability to come to terms with the reality it has created for itself in this and other matters does not preclude the realization that wars involving troops are occurring in many Muslim countries. The situation is complex, and morality is merely another weapon for proving the other guilty and oneself guiltless. The geopolitical dimensions of Islam's relationship with Europe, or India, or Thailand, or the United States, do not yield to moralizing.

Something must be done. I don't know what needs to be done, but I suspect I know what is coming. First, if it is true that Islam is merely responding to crimes against it, those crimes are not new and certainly didn't originate in the creation of Israel, the invasion of Iraq or recent events. This has been going on far longer than that. For instance, the Assassins were a secret Islamic order to make war on individuals they saw as Muslim heretics. There is nothing new in what is going on, and it will not end if peace comes to Iraq, Muslims occupy Kashmir or Israel is destroyed. Nor is secularism about to sweep the Islamic world. The Arab Spring was a Western fantasy that the collapse of communism in 1989 was repeating itself in the Islamic world with the same results. There are certainly Muslim liberals and secularists. However, they do not control events — no single group does — and it is the events, not the theory, that shape our lives.

Europe's sense of nation is rooted in shared history, language, ethnicity and yes, in Christianity or its heir, secularism. Europe has no concept of the nation except for these things, and Muslims share in none of them. It is difficult to imagine another outcome save for another round of ghettoization and deportation. This is repulsive to the European sensibility now, but certainly not alien to European history. Unable to distinguish radical Muslims from other Muslims, Europe will increasingly and unintentionally move in this direction.

Paradoxically, this will be exactly what the radical Muslims want because it will strengthen their position in the Islamic world in general, and North Africa and Turkey in particular. But the alternative to not strengthening the radical Islamists is living with the threat of death if they are offended. And that is not going to be endured in Europe.

Perhaps a magic device will be found that will enable us to read the minds of people to determine what their ideology actually is. But given the offense many in the West have taken to governments reading emails, I doubt that they would allow this, particularly a few months from now when the murders and murderers are forgotten, and Europeans will convince themselves that the security apparatus is simply trying to oppress everyone. And of course, never minimize the oppressive potential of security forces.

The United States is different in this sense. It is an artificial regime, not a natural one. It was invented by our founders on certain principles and is open to anyone who embraces those principles. Europe's nationalism is romantic, naturalistic. It depends on bonds that stretch back through time and cannot be easily broken. But the idea of shared principles other than their own is offensive to the religious everywhere, and at this moment in history, this aversion is most commonly present among Muslims. This is a truth that must be faced.

The Mediterranean borderland was a place of conflict well before Christianity and Islam existed. It will remain a place of conflict even if both lose their vigorous love of their own beliefs. It is an illusion to believe that conflicts rooted in geography can be abolished. It is also a mistake to be so philosophical as to disengage from the human fear of being killed at your desk for your ideas. We are entering a place that has no solutions. Such a place does have decisions, and all of the choices will be bad. What has to be done will be done, and those who refused to make choices will see themselves as more moral than those who did. There is a war, and like all wars, this one is very different from the last in the way it is prosecuted. But it is war nonetheless, and denying that is denying the obvious.