In late summer last year, two United States embassies in East Africa were the target of murderous bomb attacks by Islamic terrorist groups. After ordering two retaliatory missile attacks on installations presumed to be connected with militant Islamic extremism, President Clinton hastened to assure the American people that he has nothing against Islam, which he called “a religion of peace.” In November, Islamic militants reacted violently to the progress of peace talks between Israel and the Palestine Liberation Organization with a series of terrorist attacks on Israelis, apparently with the intention of provoking a severe reaction by Israel. Again, we were assured that, contrary to the widespread impression, Islam is a peace-loving religion.

Now, it is true that Islam has many variants, although not so many as Christianity and it would be false to say that the jihad is a fundamental element in the Muslim faith, or at least a universally fundamental one. Christianity has had its Crusades and crusaders, and at one point, all of Western Christendom seemed to be focused on crusading in the East, but a simple glance at world history shows that the expansion of Islam is far more directly due to military action than is the spread of Christianity.

Generic Christians and other gentiles of our day do not hold any faith passionately enough to fight for it and find it hard to believe that adherents of another religion could actually do so in this modern age. We call our own age “post-Christian” with a certain contented smugness and proclaim it with strident voices; to borrow an expression from Père R.-L. Bruckberger, “like eunuchs proud of being castrated.” Most Christians would not think of fighting for the cause of the Christ that they are supposed to revere; they are comforted by St. Paul’s statement, “God has called us to peace” (1 Corinthians 7:15), although the context refers not to religious war, but to religious differences within a marriage.

Whenever Christians actually do take up arms in a religious context against Muslims, they are denounced in no uncertain terms by much of the Western political and media establishments. During the Lebanese civil war, it was “right-wing Christian militias” against the Muslims. In most Western reports on the former Yugoslavia, it is the Eastern Orthodox Serbs who are regularly excoriated, while the Muslim “Turks” (as the Serbs call their fellow ethnic Slavs who converted to Islam under the Turkish domination) and ethnic Albanians are eulogized as freedom fighters. Even most Jews tend not to want to recognize the religious dimension of the problems that Israel has with the mostly Muslim Palestinians.

This naive insouciance with respect to Muslim aggressiveness is possible only if one is determined to disregard both history and present-day experience. Paul warns—in another context, it is true—”If the trumpet give an uncertain sound, who shall prepare himself to the battle?” (1 Corinthians 14:8). At an interfaith meeting in 1995 held in Aiken, South Carolina, Boston College professor Peter Kreeft called for an “ecumenical jihad.” The “five kings of orthodoxy”—Roman Catholicism, Eastern Orthodoxy, evangelical Protestantism, conservative Judaism, and (presumably non-fundamentalist) Islam were to unite to defeat the virulent forces of secularism. Unfortunately for Professor Kreeft’s metaphor, jihad is defined as “a holy war waged on behalf of Islam as a religious duty,” or “a bitter strife or crusade undertaken in the spirit of a holy war,” and this does not harmonize well with ecumenical fraternizing. If there is to be a jihad involving Muslims, Christians, and Jews, it will not be cooperative but confrontational, and it will not be very quiet or very comfortable for us other “peoples of the Book.”

Who is violent in today’s “post-Christian” world? We are well informed about violence perpetrated by the nominally Orthodox Christian Serbs against the “Turks” of Bosnia-Herzegovina and the ethnic Albanians of Kosovo. We hear very little, if anything, of the atrocities perpetrated by the “Turks” and ethnic Albanians against the Serbs, nor of the fact that the Muslims of Bosnia were the allies of the Nazis against the Serbs during World War II. Those “Turks” are ethnic Slavs who converted to Islam during the period of Turkish rule; the Albanian Muslims also came from a population, once Christian, which converted under the Turks and helped the Turks control their subject Christian majority. The Slavs have bitter memories of past Muslim terrors; when Polish children misbehaved, mothers used to warn them, “The Turks will get you,” reflecting centuries of Christian experience under the crescent moon. The fierce resentment that the Serbs feel at attempts to dismember what remains of their once substantial realm stems from that bitter history as well as from present-day antagonism.

Do the Muslims of today, in their majority, repudiate violence the way Christians are taught to feel shame for the Crusades? The rapid expansion of Islam, unlike that of Christianity in its early centuries, came in the wake of Arab conquests, which wiped out the Persian Empire and destroyed Zoroastrianism before proceeding to the subjugation of much of West Asia, North Africa, and Spain. Syria and Egypt fell; the library of Alexandria, the greatest in the ancient world and one of the jewels of Christian culture, was wantonly destroyed by the invaders. It is self-evident that Islam, far more than any other religion, owed its expansion to military aggression.

Although the eastern horn of the Islamic crescent was blunted in the waters around Constantinople in 678, Arabs pushed up the Iberian peninsula into France, until the western horn was finally broken by Charles Martel at Tours in 732 (a second Arab attempt to take Constantinople had failed in 718). The Christians of the Iberian peninsula took more than seven centuries to push the Islamic Moors back across the Straits of Gibraltar. (The 500th anniversary of this victory, 1492, was passed over in embarrassment as politically incorrect to celebrate, like Columbus’s discovery that same year.)

After the turn of the millennium, in the East, the Muslim Turks took over from the Arabs the attempts to overrun Christendom, eventually conquering Constantinople in 1453, having previously crossed the Bosphorus and established themselves in Greece and the Balkan peninsula. Most of Eastern Christendom was plunged into a prolonged darkness of the kind that the Nazis briefly visited on occupied France in 1940-1944. During this period, Islam—by conquest, trade, and missionary expansion—swept over India, down the Malay peninsula, into the islands of the East Indies, and up into central Asia, but much of this went relatively unnoticed in the West and plays an insignificant role in our courses in “world history.”

Islamic pressure on the Christian nations of southeastern Europe, with which we are more familiar, reached the gates of Vienna before being thrown back in 1526; a second and—up until now—last attempt was made in 1683: The Turkish armies were defeated before the walls of Vienna by a coalition led by the Polish king, John Sobieski. That was the high-water mark of Islamic expansion. After that, the Islamic tide receded in North Africa, Egypt, Syria, Lebanon, and Arabia, beginning two and a half centuries of retreat. The rise of industrialism, Western science, and the European conquest and colonization of the Americas was followed by a steady pressure on what had been Muslim strongholds in Africa and the Near East. The ancient seats of Western culture in Greece were recovered early in the 19th century, and the Orthodox Balkan peoples gradually gained their independence, but even the defeat of Turkey in World War I could not restore Constantinople to the Creeks.

That defeat of the Turkish Empire in World War I was followed by the temporary establishment of Britain and France in the Near East. After the reluctant departure of the British and French after World War II, the Islamic expansion began again, this time under Arab, rather than Turkish, auspices. While European hegemony had seemed destined for a millennial reign at the end of the 19th century, the 20th has proved it to be as frail as the Christian Kingdom of Jerusalem and the other temporary conquests of the Crusades.

What Islam proved unable to achieve by military means, either against the industrialized nations of the West or against the Jewish immigrants in the Holy Land, it is now accomplishing by other means, by an Islamic version of the Völkerwanderungen that overwhelmed the Western Roman Empire. Populations are being violently displaced; the highly publicized “ethnic cleansing” with which the Serbs are charged is but a pale reflection of what the Muslim Turks did to their Armenian Christian population in the second decade of this century. At the beginning of this century, one-third of the people of what is now Turkey were Christians, but the persecution and genocide of the Armenians early in the century, and the flight of Creeks after their ill-fated attempt to recover Constantinople following World War II, have left Turkey with only a tiny fraction of non-Muslims today. Even Israel may ultimately be more Muslim than Jewish.

The nations of the West still possess highly refined weapons and, in many cases, well-trained and numerous military forces. It would be suicidal for Turkey to attempt to storm Germany or for the Algerians to assault France. But Western Europe is gradually being subjected to invasion by immigration, if we can call it that. The Turkish population of Germany is large and growing, and the new Socialist-Green government, which is openly hostile to Christianity, intends to make their presence permanent without Germanizing anything but their language. A similar phenomenon exists in France, where the native French population is stagnating while the Algerian and other North African presence grows, only slightly moderated by the presence of African Christians. The wandering Volk may accomplish what no invading army could do.

The establishment of the state of Israel and the hitherto unsuccessful attempts of the Arabs to dislodge it by war (declared and undeclared) or by terrorism have diverted attention from the fact that Islam is spreading everywhere by what appears to be an inexorable biological energy. After the end of French rule, Algeria has been “ethnically cleansed,” if we may use that phrase, of its substantial European minority. With the end of colonial rule, Muslim rulers in several African states, without regard to the presence of large numbers of Christians and adherents of African tribal religions, are establishing Islamic Shari’a law, often with tremendous cruelty, noticed by its victims, but not by the West. Both Christians and animists in the Sudan are fair game for Muslim slave-traders.

The pressure and atrocities committed by adherents of Islam in Africa merit little attention in Western diplomatic circles and in the press. The African Christians and animists, like the Lebanese “right-wing Christian militias,” belong to what Jacques Ellul called the “uninteresting poor,” whose sufferings interest only themselves.

The Roman Empire in the West was becoming Christian before it was overwhelmed and subjugated by the Völkerwanderungen of the Germanic peoples. The success of the barbarians in penetrating and overthrowing the empire in the West was facilitated by the moral and spiritual fatigue of the old Romans. The imperial idea was no longer commanding, but Christianity was there as a vital force for the rebuilding of the ancient world. The resulting interaction between Hellenistic culture, Christian faith, and the vigor of the barbarians produced “Christian culture” and Christendom.

The peoples of the West are tired, having exhausted much of their strength in what amounted to wars of extermination in the first half of this century. Reformed demographer Pierre Chaunu speaks of a “demographic winter,” of the gradual dying out of whole populations. But the Muslim peoples, after centuries of stagnation, are resurgent. They, too, may experience a demographic winter, but it will set in later. Their old ambitions again seem within their reach, stiengthened as they are by the tremendous importance of their vast reserves of oil. Many of the tiaditional religious foundations of the West are eroded; it is not yet apparent whether emergent signs of revival indicate a rejuvenation of Christendom or only a few “brands snatched from the burning.” Nominal Christians seem to care little for the fate of their religion or even the destiny of their nations; fervent and convinced Christians, fewer in number, are surely more vigorous, but the eyes of many are fixed on the “city that is to come” (Hebrews 13:14). Is there enough vision and stiength to rebuild the walls of the West? Or will we succumb to a quiet jihad, in which what could not be gained by violence is achieved by erosion?