The expansion of Christianity in Africa and Asia is something of crucial significance for the Western world, as much as it would like to sweep Christianity under the rug. Philip Jenkins argues that  this is causing a violent backlash from Muslims whose dominance is being threatened by growing Christian populations.

...Christianity, which a century ago was overwhelmingly the religion of Europe and the Americas, has undertaken a historic advance into Africa and Asia. In 1900, Africa had just 10 million Christians, representing around 10 percent of the continental population. By 2000, that figure had swollen to over 360 million, or 46 percent of the population. Over the course of the 20th century, millions of Africans transferred their allegiance from traditional primal faiths to one of the two great world religions, Christianity or Islam—but they demonstrated an overwhelming preference for the former. Around 40 percent of Africa’s population became Christian, compared to just 10 percent who chose Islam. As Muslims had earlier far outnumbered Christians, the result was to transform a massive Muslim majority into a reasonably equal confessional balance. Africa today is about 47 percent Christian, 45 percent Muslim, and some 8 percent followers of primal religions.

To appreciate this transformation, consider Nigeria. In 1900, the lands that would become that nation were about 28 percent Muslim and 1 percent Christian. Confident in their numbers, Muslims did not need even to think about Christians as rivals. For Muslims, the pagan population represented an inferior state of being, peoples to be ruled and, often, enslaved. One day in the future, the heathens might join the modern religious world, but it would be the world of Islam. But then things went wrong. By 1970, Muslims had increased their share of the population to 45 percent. But that 1 percent Christian minority had expanded incredibly, also to 45 percent. A land that seemed firmly under Muslim hegemony was suddenly split down the middle.

The question now was just how much further Christian numbers could grow. If you extrapolate recent Christian growth into the near future, no Muslim majority seems safe, even in a place like Nigeria, where some polls in recent years have suggested an outright Christian majority. (More conservative estimates register around 46 percent.) Even nonpolitical Muslims worry: might their grandchildren be kaffirs? Worse, these newer Christians are not like the minority communities familiar in a Middle Eastern context, groups like the Egyptian Copts, who of necessity were politically quietist: the new African believers are dynamic and expansionist. The most successful follow energetic Pentecostal and evangelical forms of faith rather than the sober liturgical habits of older groupings.

The new believers draw on Western, and specifically American, forms of evangelism, marketing their faith through videos and DVDs. They organize crusades and mass meetings for prayer and healing that can draw 2 million believers together in a single venue. For nervous Muslims, the Christian threat was epitomized by the legendary “Jesus” video, originally a British film biography produced in 1979, but subsequently promoted around the world. As a weapon of mass instruction, it has few equals. Christians in Jos or Jakarta would approach Muslims and offer to show them a really interesting film about the prophet Jesus. Many accepted the invitation, and some then decided to follow the Christian way rather than the path of Islam.

Christianity also attracted independent-minded women. In traditional societies, conversion occurred when the head of a clan or family accepted a new religion and brought his kin with him. Now, when a patriarch accepted Islam, youngsters demurred, preferring to seek personal salvation in Christianity. And inconceivably, women even refused to accept arranged marriages to suitable Muslim men. Religious splits became family feuds, escalating the potential for malice and retaliation.

Few Asian countries have seen anything like the Christian growth that characterizes Africa, but here, too, religious change generates social tensions. In lands like Indonesia and Malaysia, Christianity has been associated above all with minority communities, especially the Chinese, whom majority Muslim groups hate and fear for being rich, clannish, and arrogant. Economic crises, such as the Asian financial crash of 1997-98, bring ethnic conflicts, which bear a religious coloring.

In different societies, then, booming Christianity came to be associated with a variety of perils: the breakup of traditional communities, individualism, women’s independence, and everything associated with “the West”—libertarianism, sexual explicitness, and cultural aggression. When the Pentecostal movement reached full force, all these trends began to look like a juggernaut that might overwhelm familiar cultures. From an Islamic viewpoint, these things might be troubling enough if they were happening on the traditional Muslim-Christian frontier—say in the Mediterranean—but suddenly Christian expansion was accelerating in what should have been dependable Muslim territory.

This was the package of nightmares that faced Muslim communities from the 1970s onward, at exactly the time that a new countermovement, quite as radical in its own way, emerged from the Middle East. The key date was 1979, the year of the Iranian Revolution, but also of the radical coup against the Grand Mosque in Mecca. The Saudi regime survived that assault but in a chastened mood. Anxious to prevent a repeat performance, the Saudis made their devil’s bargain with the Islamists: go and do what you like around the world, and we will bankroll you, but stay out of our own beloved kingdom. That was the point at which Gulf oil money began rolling around the Muslim world, funding mosques and madrassas following the hardest of Islamist lines. By the end of 1979, the Soviet Union had invaded Afghanistan, sparking a war that would become a vehicle for training jihadis worldwide.

The outcome was a new and highly militant form of Islam, impatient with old-style moderate forms of faith and fanatically opposed to Christian incursions into continents seen as Muslim realms. For these militants, the growth of Christianity was proof of the failure of the old Muslim regimes. In the words of radical theorist Sayyid Qutb, these regimes had shown themselves infidels at heart, and it was up to true Muslims to condemn them as such (takfir) and remove themselves spiritually (make hijra) to a new and purer activism. In 1989, a revolutionary Islamist regime took power in the Sudan. The same year, at Abuja in Nigeria, a conference on Islam in Africa outlined a program for successful Islamization. That event entered Christian folklore, and one does not have to travel far on the continent to hear claims of all manner of secret plans to destroy Christianity across Africa and create a caliphate. If Islamists denounce the Christians as tools of America, Christians everywhere see the hand of Riyadh.

In many countries, Islamist sects formed militias, some affiliated with the nascent al-Qaeda. In 1993, for instance, Indonesian extremists formed the terrorist organization Jemaah Islamiyah, which would be responsible for the 2002 bombings that killed 200 in Bali. One of the deadliest anti-Christian groups in West Africa has been the al-Qaeda-linked “Nigerian Taliban,” known to themselves as the muhajiroun—those who make hijra.

When we see interfaith battles in Africa or Asia, we are generally not witnessing activism by al-Qaeda militants directed from some secret terrorist mission control, but we do find movements driven by exactly the same grievances that motivate bin Laden’s associates—above all, we see the same central fear of Christian expansion. For Muslims, whether political dissidents or actual Islamists, the world is evidently engaged in a culture war, a war of faiths, and groups like al-Qaeda are only one small and sensationalized portion of that. Christians likewise know the stakes. Educated African believers look back with trepidation at the great Christian churches that flourished in the northern regions of the continent 1,500 years ago, churches that would be snuffed out under Islamic rule. They are determined not to let that disaster be repeated...