This year the leaders of France and Britain declared that their countries' policies of multiculturalism had failed. As when Germany's Angela Merkel made similar statements last year, Nicolas Sarkozy and David Cameron sparked a political firestorm.
Europe's debate over multiculturalism, and how to deal with non-European immigrants, will only intensify as the full effects of the Arab Spring play out on our continent. But it's worth stepping back to consider how we arrived at this point—how it became so controversial for a Western leader to affirm a preference for his own culture. In short, how did Europe lose confidence in its own civilization?
In their modern forms, the noble Western traditions of self-assessment and self-criticism have often degraded into sentimental self-flagellation. Consider Africa, whose underdevelopment many people blame on the West. This guilt over Africa's poverty is a sentiment that underlies Western development aid. But the question to ask is not, "Why are poor countries poor?" The right question is, "Why are wealthy countries wealthy?" In the beginning we were all poor.
Whoever wants to study the rise of the West and the roots of our prosperity should go back to the Renaissance, if not to classical antiquity. Colonizing Africa had nothing to do with it; the interior of most of Africa was inaccessible until late in the 19th century. European colonizers also came late to North Africa and the Middle East, which for many centuries was ruled by the Ottomans. Europe is no more responsible for the underdevelopment of Africa than Rome was for the underdevelopment of Gaul.
Many people also hold great sympathy with the Palestinian people. That is understandable because their situation is indeed pitiful. But who bothers about the lot of Christians in the Middle East? Their situation is at least equally pitiful as that of Palestinians, if not more so.
At least 10% of Egypt's population is Christian (Coptic). They are repressed and frequently live in misery. The Christian minorities in Syria, Iraq and Pakistan are also discriminated against. In Somalia, Islamists hunt down anyone in possession of a Bible. Yet no one in Europe seems to get excited about these crimes. Christianity appears to be a spent force in Europe, with the exceptions of Poland and Ireland. But for Christians in Asia, Africa, Arabia and beyond, it is not the anemic religion that it has become here. Third World Christians rightly feel deserted.
If they have any doubt about the importance of Christianity in contemporary Western life, these non-European Christians need only look to locales such as England's Oxford. There, in a land with an established Christian church, the municipality has decided to replace Christmas with a "Winter Light Festival." According to a spokesman, this ensures that equal attention is paid to all religions.
Europeans weren't always so self-hating. The 19th century saw the high tide of imperialism, and Europe was brimming with self-confidence. What has happened? The past century witnessed the cataclysm of World War I, the rise of collectivist dictatorships during the interbellum, World War II and the Holocaust, Stalinism and the societal chaos of 1968. These events eroded our cultural certainties and ushered in the era of multiculturalism, which enjoins us "not to judge" that which is different.
The other foundation of our current masochism is, ironically, the very Christianity that modern generations have been so eager to cast off. Whether we like it or not, our civilization remains deeply marked by Christianity. Consider the Gospel of Saint Matthew, which states that "whosoever shall exalt himself shall be abased; and he that shall humble himself shall be exalted" (23:12). Friedrich Nietzsche characterized this as "slave morality." But one does not have to go that far to realize that this saying, along with instructions to "turn the other cheek" and "go the extra mile," do not exactly prod people to stick up for their own.
If Islamic civilization may be described as a shame culture, Christianity is a guilt culture. Listen to Bach's "Passion According to Saint Matthew." The chorus—that is to say the people—sings, "I shall be punished for what you [Christ] have suffered," and, "You are no sinner, like we and our children." Pride joined guilt and we in Europe soon came to believe that the mote in our eye was heavier than the beam abroad.
This would not be a problem if the burden of a bad conscience came with atonement, forgiveness, confession, expiation or any of the other theological or liturgical forms for purging guilt from the sinner. Formerly, Catholicism and Lutheranism provided for the atonement of guilt. But these traditions no longer have credibility in Europe. Feelings of guilt are not sublimated. This also goes for Calvinism, which in its purest form knows no remission of guilt in this life. Its effects have been deep in Europe and outlast the doctrine.
Thus in 1996 the Dutch government declared that its "debate about multiculturalism must be conducted on the principle that cultures are of equal merit." And so it has gone, for years. In 2002 right-wing politician Pim Fortuyn was assassinated during national elections, three months after he had called to remove an anti-discrimination clause from the Dutch constitution.
The day after his murder, the editor in chief of the NRC-Handelsblad, a leading Dutch newspaper, wrote that "The pride of the Netherlands is precisely that we do not find one culture better than the other." The writer apparently did not realize that his pride exalted Dutch culture over others—supposedly against national values.
And in 2009, when Utrecht University theologian Pieter van der Horst wanted to devote his valedictory address to "the Islamization of European Anti-Semitism," the institution forbade it, letting its fear of Islamic displeasure take precedence over another ostensibly protected right in Holland: free speech.
The effects of Christian guilt and European self-hatred can be seen around the world, having been picked up by other cultures and used against Europe. After World War II the West set up the United Nations, in part to weaken its own hegemony. Within 30 years the U.N. had grown an automatic majority bent on castigating the West and Israel. The U.N. Human Rights Council, based in Geneva, elected Libyan leader Moammar Gadhafi to join its ranks and judge the state of others' civil liberties.
For 13 years the U.N.'s Educational, Scientific and Cultural Organization (Unesco) was led by Senegalese teacher Amadou-Mohtar M'Bow, a Soviet-backed, virulent anti-Westerner who ran the organization as if it were an African village and he its tribal leader. In 1984 the U.S. pulled out of Unesco, and in 1985 the U.K. and Singapore followed suit. Continental Europe's nations remained and let themselves be duly castigated.
So much the better that a handful of European leaders now are attempting to reverse our slow cultural suicide. If Europe can retake pride in its own classical values, it and the world will be better off.
Mr. Bolkestein is an author, retired center-right Dutch politician and former European commissioner for internal market and services. 
