Who would want to kill the pope? Millions ask themselves that question and, not finding an answer, embrace the faddist theory of a terrorist plot.

In fact, the gunman was the crazed product of a notorious cultural milieu. I speak of the milieu of Islamic fundamentalism.

Islamic fundamentalism has made its mark many times in many places. The Iranian revolution and the seizure of the American hostages in Tehran were the work of Islamic fundamentalist. The murderous ruler of Libya, Muammar Qaddafi, is an Islamic fundamentalist. Similarly, the gang that occupied the Grand Mosque of Mecca back in 1979.

Most Westerners, for a variety of reasons, prefer to ignore this dark side of Islam. If nothing else, censorious scrutiny of other people's religion is a king of bad form. But what is at issue is not so much religion as sociology and politics. Islam, apart from being a personal credo, represents a system of social organization. In general, Islamic society has been characterized by economies that are agricultural and rural; by institutions that are at the level of the family, the tribe, the guild; and by customs that emphasize established hierarchies that limit mobility.

Modernization, inevitably, had a staggering impact on Islam. Rapid communication, literacy and the surging population because of improved medical care worked to break down hierarchies and promote mobility. Industry came, and with it the move to large urban centers. On top of families and tribes, there was superimposed the national state. European imperialists undoubtedly played role in bringing modern ways to Islam. But less so than often supposed. The Europeans were quickly routed by the anti-colonial movements that swept through the Middle East, Africa and Asia after World War I.

Far more important were the local elites trained in Western skills, and imbued with Western ideals. From North Africa through the Levant and the Arabian Peninsual, and on to Indonesia and the Philippines, local pro-Western elites became the chief agents of modernization in the Moslem world.

Islamic fundamentalism is in large measure a protest movement against the modernization imposed by the local elites. As Prof. M. F. Yapp, a British Islamicist, wrote in an article called "Contemporary Islamicis, Revivalism":

"As modernization proceeds, people are drawn into greater participation . . . and especially as urban immigrants. Observing the gulf which separates their conditions from that of the older Westernized elites . . . they put forward their demands in the form of an assertion that the Westernized elites have betrayed the values of Islam. . . ."

Turkey presents a striking example of that phenomenon. Modernization was imposed from above by the great reformer, Kemal Ataturk, whose centennial is being observed this week. Ataturk established a modern state, secularized Turkish society and institued as guardians of his reform a professional army.

When economic modernization picked up speed after World War II, millions of Turkish peasants left the barren eastern plains for jobs in Istanbul or, as guest workers, in the industrial centers of Western Europe. Though far better off than before, they had cut their cultural moorings and were clearly lower in status and relative wealth than many around them. Some, in protest, joined left-wing or progressive movements. Many more enlisted in a right-wing Islamic movement, the National Action Party.

Mehmet Ali Agca, the man accused of shooting the pope, is a case in point.

He migrated to Istanbul from a rural village in eastern Turkey. He fell in with the bully boys of the Action Party and engaged in regular gang warfare with the ruffians of the left. As part of that operation, he assassinated a Turkish newspaper columnist. An American diplomat who looked into the case back in 1979 describes Agca as an "Islamic fundamentalist nut."

Sympathizers in the police helped him escape after his conviction on the assassination charge. He took the passport of a friend and substituted his own photo. Then he went to Europe and migrated among various expatriate Turkish communities in Germany and Italy. Acquiring a weapon was easy, and he went after the pope as a living symbol--indeed, the most prominent example--of the spirit that breaks down the barriers the Islamic fundamentalists seek to rebuild.

So what is primarily involved in the assault upon the pope is not an organized terrorist conspiracy that can be stamped out by more police and vigilance. At the root of the assassination attempt is a turbulent Islamic society. It is a society pregnant with nasty surprises, and the large lesson is that those who look to the Moslem world as a sure supplier of oil or a steady ally against Moscow do so at their peril.