The Charlie Hebdo massacre in Paris was a watershed moment in the war on terrorism in two ways. First, it’s almost impossible to pin the murders on anything but blind adherence to religious faith. The murderers, like many Muslims, believed that making fun of or even depicting their prophet Muhammad is a capital offense. Why else would the terrorists target Charlie Hebdo instead of, say, French government offices? The religious motivation directly contradicts the many apologists who blame Islamic terrorism on the West as a reaction by the oppressed to colonialism. What has changed with this tragedy is people’s willingness to recognize that religion really does make people do terrible things.

We are experiencing a historic clash between two tenets of liberalism: multiculturalism and Enlightenment. Absorbing immigrants can enrich a society in many ways, but not if those immigrants demand a public deference to their religion that conflicts with democratic values.

I’m referring in particular to free speech: the right to criticize or make fun of anything so long as you’re not directly inciting violence. For exercising that right, 10 members of the Charlie Hebdo staff were exterminated. Not all Muslims, of course, riot or kill when Muhammad is defamed or depicted, but the view is sufficiently common that the West has finally woken up to what it means for democracy.

One would think that Catholicism, a largely Western institution, would share the solidarity among enlightened people prompted by what happened in Paris. Wrong. Pope Francis, the voice of the Vatican, has pronounced that free speech should be limited: that while satire and mockery can’t justify murder, they shouldn’t go too far—by which the Pope means that criticizing religion should be off limits.

On a trip to the Philippines this week, Francis, after decrying “murder in the name of God,” carefully delimited how far magazines like Charlie Hebdo should go: "One cannot provoke, one cannot insult other people's faith, one cannot make fun of faith."