MOHAMMED Bouyeri stunned the courtroom in Amsterdam Tuesday when he declared that he had murdered Dutch filmmaker Theo van Gogh ''out of conviction." The Dutch-born son of Moroccan immigrants, who had received a first-class secular education in the Netherlands, told the court, ''If I ever get free, I would do it again." Then the radicalized Islamist turned around and spoke to his victim's mother, Anneke van Gogh, saying: ''I don't feel your pain. I have to admit I don't have any sympathy for you. I can't feel for you because I think you're an infidel."
Because the perpetrators of last week's London bombings will remain forever mute, they cannot offer what Bouyeri's statement did -- a glimpse into the chasm that is opening up between the graying, secular, permissive societies of Europe and the predominantly young, unassimilated children and grandchildren of Muslim immigrants. This chasm is becoming a defining challenge for Europe's future. All Europeans, including Muslims who abhor Islamist terrorism and the ideology that spawns it, are affected by clashing expectations about the proper roles of religion and the state, equality between men and women, freedom of expression, and the community to which citizens should give their primary allegiance.
If Europe is to weather the challenge of accommodating an ever greater proportion of Muslims, many of whom do not want to abandon their distinct values and traditions, majorities and minorities will both have to change their ways. European societies will have to abandon a concept of assimilation that requires non-European immigrants and their descendants to replicate the mores and value systems of their French, German, or British neighbors.
Tensions in France
A dramatic illustration of this refusal to let Muslims be Muslim has been on display in the French law banning schoolgirls from wearing head scarves in public schools. This is a use of law to demand that French Muslims accept France's Republican tradition of making religion a purely private affair. Passage of the law said to Muslims in France that the state can force them to acknowledge that the public sphere must be secular.
Unlike the American concept of religious liberty as a shield against any single established religion, the French version seeks to preserve public institutions as places where the citizen enjoys freedom from religion. This principle, shaped in a centuries-long struggle between clerical and anticlerical forces in France, underlies the rhetoric of political figures such as Bernard Stasi, the chairman of the French commission that recommended the head scarf ban. To justify the ban, Stasi has said, there are ''forces in France" that ''are trying to destabilize the republic, and it's time for the republic to react."
Since the central traditions of Islam assume that faith is not to be confined to the private sphere and that, on the contrary, it is inseparable from the life of the community, the French prohibition against the head scarf is easily perceived as a sign of discrimination against Muslims because of their religion. Rather than defending the republic against Islamist radicals, the ban against head scarves has served to validate the propaganda of the radicals, who justify their cult of holy war as necessary to defend Islam against the aggressive hostility of non-Muslims.
Like the French ban on head scarves, Bouyeri's unrepentant confession of guilt reflects the gaping distance between mentalities that cannot accept -- or even understand -- each other. So shocking was the killer's unapologetic rejection of the Enlightenment value of tolerance that spectators in the courtroom rose from their chairs. They knew this was not something he had learned in the fine Dutch schools he had attended.
A challenge from within
What Bouyeri and Islamist radicals such as those involved in the Madrid and London train bombings evoke is a rejection of European values from within European societies. Theirs is an assault on Europe's social cohesion by young Muslims who speak English, French, Dutch, or Spanish, who have listened to the same music and watched the same TV fare as their fellow citizens, but who use the Internet and DVDs and their cellphones to wage jihad against the societies they live in.
Those societies will have little choice in the future but to adapt to their fellow citizens who are Muslim. And European Muslims will have to mold themselves to their European environment. Barring changes in birthrates and immigration flows that are hard to foresee, demography will dictate the need for such mutual accommodation.
There are more than 23 million Muslims in the European Union, about 5 percent of the total population. The fertility rate of Europe's Muslims is three times that of the non-Muslim population. Because of their increasing proportion of older, retired people, European countries need to take in more than 13 million migrants annually to maintain their population-support ratios (the ratio of working-age people to those 65 and over). As a result of immigration and uneven fertility rates, the Muslim population is expected to double by 2015 while the non-Muslim population declines by 3.5 percent. Some projections, based on a continuation of current trends, foresee a Muslim majority in France by 2050, and perhaps in all of Europe.
Even if those trends are altered, European Muslims and non-Muslims must learn to live together. Each will have to practice the tolerance that the assassin Bouyeri proudly scorned. European states will have to honor the Islamic ideal of religion as a way of life unifying the private and communal realms. Europe's Muslims will have to recognize that gender equality, secular law, and the right to believe in any faith or to be an unbeliever are hard-won European achievements that need not threaten a separate Islamic identity.