Not since late antiquity has the world seen a migration of peoples like the great urbanization of China now in progress. By 2025, migrants will make up two-fifths of China’s billion-strong urban population, a fifth of all the Chinese, according to the McKinsey Global Institute.

Many analysts have observed that this great confluence of ethnicities and languages has prepared the ground for a great wave of Christian conversion. At the end of World War II, with a nationalist government supportive of Christian missions, barely two percent of Chinese were Christians. The World Christian Database now counts 111 million Chinese Christians, while an internal survey conducted in 2007 by China’s government puts the number substantially higher: 130 million, nearly 10 percent of the total population.

Far less often observed”and potentially more important”is the fact that this exponential growth of Christianity in China would not have been possible without the forbearance and tacit encouragement of the regime. In recent years, the Chinese government has shifted from persecution of Christians to subtle”and sometimes even open”encouragement of Christianity. Christianity never will be a state religion in China, to be sure, and the Communist party in China is still officially atheist. But it is not an exaggeration to say we are near a Constantinian moment for the Chinese Empire, as the government looks to Christianity”particularly Catholicism”for an instrument of social cohesion.

During the 1990s, an idiosyncratic hybrid of Buddhist and Taoist beliefs called Falun Gong rapidly gained adherents in China. Founded in 1992, the Falun Gong elaborated ancient Chinese breathing exercises and meditation into an ethical system resembling a new religion. Though it suffered some minor friction with the regime and the arrest of some members, the new cult with ancient roots felt strong enough to offer a public challenge on April 25, 1999, in the form of a demonstration before Zhongnanhai, the seat of China’s government. Ten thousand elderly people from all parts of the country surrounded the leadership compound silently, refusing to speak with the police. The demonstrators appeared after China’s leaders rejected Falun Gong’s demand for official recognition.

China’s leaders had had no prior warning of the demonstration from security forces, and they subsequently determined that the protest was abetted and perhaps even organized by senior security officials. The government suspected that Falun Gong’s ringing of the presidential palace was part of an attempted putsch supported by the most xenophobic wing of the Communist party and aimed at stopping the reforms and modernization the government was attempting to advance. In June the government of Jiang Zemin banned the movement.

Nominally a spiritual movement, Falun Gong has the hallmarks of the old anti-imperial movements that sought a return to Chinese tradition. It opposes Western science and medicine in favor of ancient Chinese traditions, insisting that diseases are the outward manifestation of sins and that without sins there would be no sickness. Traditional meditation and breathing techniques are used to cast out sins.

In addition to its reactionary nostalgia, the Falun Gong has a highly structured organization (modeled after the Communist party), complete with cells, a ­central committee, and a politburo. It claimed a hundred million adherents in 1999. China’s leaders, keen students of their country’s history, saw in Falun Gong the millennial beliefs of the Buddhist-Taoist tradition, which have motivated several successful rebellions against central power, most notably the revolt of the Yellow Turbans ( a.d. 170“184), the uprising that brought down the Han dynasty. Fearing a traditionalist insurgency against its reform campaign, the Chinese government broke the back of the organization, quite roughly by most accounts.

But the Chinese leadership also drew from the episode a decisive lesson. Since the discrediting of Maoism twenty years earlier, China had been living with no cohesive set of values. The Maoist model had offered a form of secular religion”a religion that had supplanted the old imperial ideology founded on Confucian civic morality and Buddhist-Taoist religious belief. The successive assault by modern Western ideas and communist ideology erased the old imperial ideology, and the collapse of the communist model left China with a spiritual vacuum.

Rushing in to fill this vacuum in the early 1980s were a variety of qigong , spiritual breathing exercises with roots in Taoism and Buddhism, of which Falun Gong was the best organized. As one senior government official told me after the crackdown in 2000, “The fact that so many people believed in this mumbo-jumbo changed the debate in the party. It proved that it was not that reforms were going too fast; the problem was that reforms were going too slowly.”

The Chinese Communist party’s belated recognition that a backward-looking traditionalist movement might overthrow its reform campaign and stop the modernization of China led some its leaders to a radical conclusion. In a now famous essay, one of the youngest important party officials, Pan Yue, argued that religion might well be the opiate of the masses but that the Communist party needs just such an opiate to keep power as it changes from a revolutionary to a ruling party. The party, he argued, needs to learn how to use religion to enhance social stability and to avert rebellions and revolutions.

One result was a world conference on Buddhism, held in Hangzhou in 2006 and attended by President Hu Jintao. Another was the 2007 revision of the party constitution. But the decisive result of China’s reconsideration of religion may have been the Seventeenth Party Congress, held in Beijing in October 2007. Religious affiliation is forbidden for party members”but there, in close-ups on television screens showing the plenary session in the cavernous Great Hall of the People, was the slim and attentive face of the young Panchen Lama, the second-ranking figure in Tibetan Buddhism, listening to Hu Jintao’s speech. The badge on his chest read “Guest.”

The close-up sent a message that the important religious dignitary in Tibet was supportive of the Beijing government, certainly. But it also sent a message that the party was reconsidering its stance on religion. Hu’s keynote speech reserved a paragraph for religion, emphasizing that religious people”priests, monks, and lay believers”played a positive role in the social and economic development of China. In the official version of the text, Hu is quoted as saying that the party must mobilize the positive elements of religion for economic and social development. Thus, religion can play an important role in realizing the “harmonious society” that is the new political goal of the party.

Two months later, on December 18, 2007, the Chinese Politburo held an extraordinary meeting. All twenty-three members of China’s top leadership gathered for a daylong set of lectures on the subject of Christianity”and, even more significantly, announced that it was doing so: an unambiguous signal to the public that the Communist party now approved of the practice of Christianity alongside Buddhism and ­Confucianism.

The identity of the speakers and the topics of their presentations were made public, although the proceedings were kept private; one can only imagine what sort of questions China’s communist leaders put to their experts on the subject of Christian theology. But what was not left to the imagination was the fact that the Politburo had gathered to take instruction in Christianity”and, by way of followup, the Politburo commissioned a series of reports on Catholicism from a professor at the Chinese Academy of Social Sciences, Ren Yanli, the foremost Chinese academic specialist on the Catholic Church.

Officially, the Chinese Communist party’s newly benign attitude toward religion is strictly instrumental, and it extends to Buddhism as well as Christianity. The 2006 world conference on Buddhism was followed by a similar event in 2009. Delegations from fifty countries attended, and the Panchen Lama, in a sign of internationalizing the conference, spoke in English. Buddhism, it should be noted, has a special importance as a unifying factor for the mainland and Taiwan and thus plays a unique role in the Chinese government’s policy. Because it fosters the goal of reunficiation, Buddhism predictably received the blessing of the Communist party.

Far less predictable is the unprecented sympathy that China has shown toward Christianity. The leadership views Christianity in a fundamentally different way from how it sees the religions rooted in traditional China. Christianity is inherently open to the modern world and a scientific outlook. Just as China imported science and Western methods of industrial organization, so it could import what Beijing understood to be the spiritual counterpart of Western science. In the view of the party, the naturalization of Christianity in China is not essentially different from the importation of socialist ideology two generations earlier. Christianity, like socialism, can be translated into Chinese characters.

Once it seemed to be sanctioned by the government, Christianity redoubled its rate of expansion. It is now fashionable to wear a cross, hanging from a small chain at the neck, fully exposed on the chest. Asked about the meaning of the cross, the wearer will answer proudly and clearly: “Yes, I am a Christian””though few of them can give a clear explanation of what they believe. Most Chinese Christians do not know the difference between being Protestant ( jidujiao ) and being Catholic ( tianzhujiao ).

Many of these new Chinese Christians are converts to modernity and Western culture as much as they are converts to a religion that, in China, is associated with Westernization and the American way of life. Attending Christian services forms part of a new embrace of Western culture, including everything from classical music to Kentucky Fried Chicken (the fastest-growing field of study and restaurant chain in China, respectively). In the same way that they add soy sauce or rice vinegar to American-style food, Chinese frequently spice their evangelical faith with belief in feng shui (“wind and water,” traditional Chinese geomancy) and the Yijing (an ancient soothsayers’ manual).

While these qualifications make it difficult to assess the depth of Christian conversion in China, the breadth is astonishing. China’s government is still trying to assemble a comprehensive picture of the Chinese who profess faith in Christ, but it has not succeeded in doing so. Catholics”including those registered with the official Patriotic Association and those officially considered “still underground””number between 12 and 14 million. The rest are Protestants, with a smattering of Russian Orthodox, Jehovah’s Witnesses, and Mormons.

In many areas the local pastor is influential, and the local party chief has to discuss with him the enforcement of regulations or the beginning of new policies. This dialogue between religious and political powers is officially forbidden, but the party also encourages a policy of social harmony and thus tries to avoid social confrontations, which encourages local officials to reach an agreement with the local religious leaders.

Many of those pastors are self-taught, having read a translation of the Bible in Chinese. The translator may be neither accurate nor scholarly, and their preaching typically draws more from local Chinese lore than from the Bible. Many pastors mix Christianity with Taoism and Buddhism.

For the most part, Chinese Christianity remains an unstable mixture of Christian and traditional elements. The ambiguity of Christian belief has its counterpart in instability on the ground. There have been reports recently, from provinces such as Hebei, of fights between villages in the name of religion. Neighboring villages who have joined different Christian or Buddhist sects have come to blows. Hebei is China’s heartland; it was the breeding ground for the Boxer Rebellion, an uprising by militant traditionalists who fought Western influences at the turn of the twentieth century. Keenly aware of the violent history of religion in China, Beijing wants to suppress the potential for clashes over religion.

That helps explain Beijing’s special interest in Catholicism as a potential unifying force. On the face of it, the loosely organized and geographically dispersed Protestant churches may seem less of a threat to party rule than does the international organization and unity of the Catholic Church. But the Catholic Church remains of far greater interest to the authorities than the amorphous and sometimes ephemeral denominations that comprise the “house churches.”

That is partly because China’s Catholics have shown no interest in politics, despite decades of repression: During the 1989 Tiananmen Square protests, for example, Bishop Joseph Zen of Hong Kong ordered priests and congregants to keep out of the demonstrations. But the Communist party’s attitude has much to do as well with their worries about the unstable combination of traditional elements among the endlessly diverse Chinese Protestants.

Beijing views the Catholic Church as an unambiguously Western embodiment of Christianity, untainted by syncretic confusion and therefore indispensable to the Westernization of China. The Chinese government wants to deal with a Christian Church that preaches values compatible with modernization, preferably one that has a transparent and coherent organization. Although its public stance is positive toward Christianity in general, in practice the government’s efforts to develop relations with Christians have been concentrated on the Catholic Church. Chinese diplomacy has devoted a disproportionate amount of attention to the revival of relations between Beijing and the Vatican.

The negotiations have been halting, with missteps on both sides, and have been complicated by the longstanding split between the official and the underground Catholic churches”though the new Chinese openness to Christianity suggests the prospect of a healing of the split.

The first attempt at reconciliation between Beijing and the Vatican failed miserably under circumstances that still are unclear. Beijing had wanted to normalize ties in 2001, acceding to most of the Vatican’s requests. China, however, learned that the Vatican wanted to canonize 120 Chinese martyrs on October 1, 2001, China’s National Day. Beijing interpreted the choice of day as a provocation and took further umbrage from the fact that many of the martyrs had died at the hands of the Chinese government (although none of the saints was martyred after 1949). The failure of the 2001 rapprochement represented a major loss of face for China and for its then president, Jiang Zemin, who had personally pushed for the rapprochement.

A freeze ensued for several years, but relations seem to be recovering. The greatest challenge to both the Vatican and the Chinese leadership is not diplomacy but the split between the patriotic and the underground churches. After years of isolation from Rome, parts of the underground church”notionally the Chinese Catholic Church, which is currently most obedient to Rome”are locked into improvisations of liturgy and doctrine that are hard to suppress and potentially embarrassing. The Vatican cannot cut the underground Catholics adrift after their long years of loyalty, often under frightful circumstances, but it cannot easily integrate them either. In some provinces, underground Catholics maintained their independence both from the Chinese government and from the Vatican, and they now answer to no one.

“This task will not be easy, and it will take many years,” a senior Vatican diplomat told me. “This is all we will have to do for many future years, to heal the past sufferings concretely, community by community. We have to do it in the spirit of the pope’s [May 27, 2007] letter: Make people understand that they have to be and can be good Catholics and good Chinese. There must not be contradictions between the two.”

Beijing always has such priorities as the economy, unemployment, ties with Taiwan, and relations with the United States”all good reasons to put the Catholic issue on the back burner. But Catholics could become a major issue for Beijing if radicals get the upper hand. The Chinese leadership has trouble understanding what the power of the Catholic Church is and to what extent it might represent a benefit or a danger.

The trouble is that Beijing thinks of the Vatican in purely political terms and cannot quite grasp that the mission of the Church is spiritual rather than temporal. China’s leaders simply do not have the historical and cultural references to understand the Church after the Second Vatican Council. Beijing wants to offer Rome a minimum presence on a trial basis, waiting to see the result. In turn, Rome is wary that the Chinese Communist party will exploit ties with Rome without making the substantial concessions required for effective communication between the Vatican and Chinese Catholics.

History has produced a great moment, but the diplomats have not yet risen to the occasion. Lack of trust and insight could easily undo China’s Constantinian moment, but the possibility of that moment nonetheless exists. It is one of the great ironies of our time: An officially atheistic government looks to religion to fill the void that its discredited Communist ideology was once assumed to have eliminated”and it asks the Catholic Church, the old enemy of Communism, to provide the best and most modern form of social cohesion.

Francesco Sisci is the Beijing-based Asia editor of La Stampa. He served as cultural attaché of the Italian embassy in China and is coauthor, with Fr. Francesco Strazzari, of Santa Sede“Cina: L’Incomprehensione Antica, L’Interrogativo Presente.