Is immigration good for Christianity?

Rory Stewart versus J.D. Vance

An audio version of this essay – read by me – is available below the paywall.

For the purposes of this essay, I’m going to assume that Christianity isn’t true. Believers, I apologise. Non-believers, bear with me. I’m going to cast a cold, analytical eye over the state of Christianity in the modern West, and offer some predictions that are informed, not by faith, but by the social sciences.

My guiding star is Rodney Stark, the sociologist whose classic 1996 book The Rise of Christianity sought to explain the growth of Christianity in purely sociological terms. Several months after the Crucifixion, Acts 1:15 suggests that there were just 120 Christians. Three hundred years later, there were millions, suggesting a growth rate of 40 percent per decade. The Rise of Christianity offers a series of sociological explanations for this extraordinary rate of growth, identifying crucial doctrinal differences between the Early Church and Roman paganism that led the former to outcompete the latter and, eventually, become the world’s largest religion.

Before Stark, most historians had assumed that Christianity initially spread through mass conversions. Although these certainly did happen, it now seems that differential fertility rates were the more important factor. Roman fertility began to decline significantly after the reign of Augustus, a consequence of low marriage rates, widespread use of (somewhat effective) contraception, preference for non-procreative sex acts, high abortion rates, and high infanticide rates, particularly for female babies. This last factor led to a substantial shortage of women relative to men – Stark estimates that there were 130 men to every 100 women – and this was made worse by the lethal danger associated with Roman abortion methods. As Stark writes:

In addition to infanticide, fertility was greatly reduced in the Greco-Roman world by the very frequent recourse to abortion. The literature details an amazingly large number of abortion techniques—the more effective of which were exceedingly dangerous. Thus abortion not only prevented many births, it killed many women before they could make their contribution to fertility, and it resulted in a substantial incidence of infertility in women who survived abortions.

Christians preached the opposite of all this. From the very beginning, abortion and infanticide were forbidden. Contraception and non-procreative sex acts were also stigmatised. Marriage was not just encouraged, but sanctified, and men were commanded to love their wives. For these reasons and more, Christianity attracted a disproportionate number of female converts, and Christian women were less likely to have been made infertile by abortion injuries, meaning that they were able to have more children. Christian birth rates soared.

Other behaviours contributed to the survival of early Christians and therefore of Christianity. For instance the Christian practice of nursing the sick meant that Christians were more likely to survive the plagues that swept across the late Roman Empire. The early martyrs also attracted converts by offering a very public and compelling demonstration of the strength of their faith. Add to this the fact that Christianity forbids the abuse of women, children, the sick, and the poor – which is to say, most people. It offers the lowliest believers hope, not just for the next life, but also for this one. “Perhaps above all else,” writes Stark in his concluding chapter, “Christianity brought a new conception of humanity to a world saturated with capricious cruelty and the vicarious love of death.”

So much for Christianity’s first millennium. Now, what of its third?

Last week, Twitter witnessed a heated theological debate between American Vice President J.D. Vance and British politician-turned-podcaster Rory Stewart. To summarise briefly, Vance asserted that a truly Christian immigration policy ought to prioritise love for one’s family, neighbours, and fellow countrymen over love for the stranger, i.e. St Augustine’s idea of the ordo amoris. Stewart disagreed, condemning politicians who “assume to speak for Jesus, and tell us in which order to love.”

I am no theologian, and so must defer to others on the question of scripture. In support of Vance, I can recommend James Orr for First Things, as well as Rusty Reno for Compact Magazine. In support of Stewart one can read Owen Strachan and James Martin. Glen Scrivener also provided an excellent overview. This is a very old dispute, and the Bible is not easy to interpret – on this question, as well on many others. One can make a good faith argument for both positions.

I’m not here to adjudicate the true Christian position, but rather – again, believers, forgive me – the position most likely to lead to the growth and survival of Christianity. Should Christian (or formerly Christian) countries accept large numbers of migrants, particularly from non-Christian parts of the world? Not “would that be a moral choice?” or “does the Church leadership tell us to?” but “would this lead to the growth and survival of Christianity?”

The British writer Tomiwa Owolade is among those who give a resounding ‘yes.’ Writing in the New Statesman, Owolade points out that:

Black west African people in Britain are far more likely to be Christian than white British people. This explains why London is the most socially conservative city in the country. According to research by the Christian think tank Theos, 24 per cent of Londoners think sex before marriage is at least sometimes wrong, compared with 13 per cent of the population. London is also the most homophobic city in the country: 29 per cent of people in London think homosexuality is wrong, while 23 per cent outside London take that view. If conservative thinkers want to stem the tide of secularisation, they should welcome immigration and the changing ethnic makeup of the country… The future of religion, including Christianity, in England is to be found among black and brown people.

A similar argument could be made of American immigration patterns, given that Hispanics tend to be both more Christian and more observant than non-Hispanics. A Pew Research study from 2020 found that Christians make up a much larger share of migrants (47%) than they do of the world’s population (30%). If a rich country like Britain or America opens its borders, it will almost certainly receive a lot of extra Christians. A win for the church, no?

I’m not so sure. Following the example of Rodney Stark, I can see a few problems with this argument on a purely sociological level:

1) Moving to a low fertility society suppresses the fertility of migrants, even if they come from very high fertility societies. A Christian from say, Nigeria (TFR 5.14) will almost certainly have fewer descendants if she moves to, say, Britain (TFR 1.57). What’s more, her descendants are more likely to secularise if they are living in the West: this paper suggests that Christian immigrants become less religious over the generations, whereas Muslim immigrants do not. Therefore, the total number of Christians in the world will be lower as a consequence of her migration.

2) To draw from another sociology classic, Robert Putnam’s Bowling Alone, high levels of ethnic diversity tend to inspire people to (as Putnam terms it) “hunker down” – they become less trusting (including of members of their own ethnic group), less altruistic, less cooperative, less inclined to make friends, and less likely to participate in communal activities. This hunkering down effect doesn’t cause Christians to immediately lose their faith, but they may be less likely to participate in communal expressions of that faith, which causes them to drift from it over time. While Owolade is right that Christian immigrants to Britain are more religious, it’s also true that British churches are highly self-segregated, which means that this piousness is unlikely to rub off on native worshipers. The data suggests that Christian immigrants become less religious over the generations, and it may also be that the secularisation of the native population is partly a consequence of increased ethnic diversity. End result: fewer Christians over time.

3) 47% of the world’s migrants may be Christian, but that means that 53% are not. The group of migrants who present the greatest challenge to Christianity are Muslims – not necessarily because they are more numerous than any other group, but because they are brimming over with what Ibn Khaldun termed asabiyyah. Note the mass demonstrations in Western cities in support of the Palestinian cause, attended by Muslims of every ethnic background. It’s impossible to imagine Christians turning out in such numbers in support of their suffering co-religionists, and not because there is any lack of Christian persecution worldwide. Note also the de facto blasphemy laws that are developing across the West, including in Britain, where a man was last week charged with a crime for burning a Quran in Manchester City centre. This in the same country in which Christians have been prosecuted for silently praying near abortion clinics. Christians may outnumber Muslims in Britain by a factor of 6 to 1, but they are completely outgunned in terms of cultural confidence, and that is particularly true of the Rory Stewart variety of Christians, who can best be described as ethnomasochistic. It’s worth noting that Stewart does not seem to be especially committed to his faith: he has mentioned in interviews that he’s an Anglican, but apparently does not write about Christianity in his autobiography, except for one mention of being accosted by a Brexiteer at church. Vance, in contrast, is a Catholic convert who attends the traditional Latin Mass and speaks often of his faith. Which of the two men exudes the most asabiyyah? Whose worldview is least likely to bend to accommodate the demands of outsiders? I think the answer is obvious.

Stewart is certainly right on one thing, however: anti-racism has always been a feature of Christianity. As Rodney Stark writes:

[A] major way in which Christianity served as a revitalization movement within the empire was in offering a coherent culture that was entirely stripped of ethnicity. All were welcome without need to dispense with ethnic ties… In this way Christianity first evaded and then overwhelmed the ethnic barrier that had prevented Judaism from serving as the basis for revitalization.

The question facing Christianity in its third millennium is how this anti-racism ought to be expressed in the age of the jet engine, when it has become so very much easier for people to migrate across the world. I once heard Francis Spufford point out in an interview that, however the church changes in the coming centuries, it will be both utterly strange to us, and also immediately recognisable as Christianity. I think he’s right. The faith is not going to die.

But any future church will necessarily be the beneficiary of doctrines that enabled its survival in 2025. That will surely include doctrines that encourage fertility, as in traditional Catholicism, and attract converts, as in Pentecostalism. When it comes to the question of border policy, and indeed the ordo amoris, my suspicion – and I may well be wrong on this – is that J.D. Vance’s version of Christianity is more likely to withstand the coming centuries than is Rory Stewart’s. Which is, perhaps, exactly what God intends.