One of the debates that keeps swirling around amongst Christians in our post-Christian society is what attitude we should take towards secularization. There are Christians who believe that secularization is a good thing, since power and influence are inherently corrupting, and it's better for Christians to be swimming against the tide than sunning themselves in the world's favour.
On the other hand, there are Christians (nearly all of whom are Catholic or Orthodox) who seem intent upon a restoration of Christendom. They formulate blueprints for a Catholic society, and don't seem in the least bit put out by the unlikelihood of these blueprints being actualised any time soon. Talking to them can be quite disorientating; for them, it seems, the High Middle Ages were only yesterday, and everything that's happened since is simply (to quote Ron Swanson from Parks and Recreations) a mistake.
I take a different view from both of these. I don't think secularisation is a good thing. But I don't pine for a restoration of Christendom, either.
I think the crucial distinction here is between religion itself and the social order. To welcome secularisation itself, or even to be indifferent to it, is to accept that human beings-- who are, as the Catechism tells us, inherently religious beings-- are frustrating their own deepest nature. That can't be good, can it?
On the other hand, I see no reason to believe that the social order which accompanied a particular era of Catholic history is replicable in today's world-- even if every single person in a given society were to become Catholic. The realities of technology, the economy, and the international order have changed drastically.
Yes, there is such a thing as Catholic social teaching, but (as Pope Benedict put it in Caritas in Veritate) "The Church does not have technical solutions to offer and does not claim to interfere in any way in the politics of states.” Thinking in terms of a Catholic social order is, I think we can say, a mistake. Rather we should think in terms of the Catholic principles (solidarity, subsidiarity, human dignity) which can pervade any number of different social orders.
And surely it's a good thing for these principles to pervade society? Accepting that Christians usually fall short of their ideals, even egregiously so, surely any attempt to live up to that ideal is good in itself? For instance, it seems silly to argue that Christianity had no buttressing effect on the institution of marriage, throughout the centuries it dominated European and American society. And the same applies to abortion, euthanasia, indecency, and so forth.
As well as this, I think it's fair to say that Christianity has an ennobling effect on culture. Even the darkest product of Christendom, such as Matthias Grunewald's depictions of the Crucifixion, never descend to the depths of nihilism and cynicism seen in post-Christian art and entertainment.
From a purely spiritual point of view, I think it's also desirable for Christianity to pervade society as much as possible. The argument is often made that bad Christianity will drive people away from religion altogether. I've seen examples of that. But I believe that it's much more important that people should hear about God, Jesus, the soul, sin, grace, and all the other concepts of Christianity. And not only hear about them as one piece of general knowledge amongst many others, but with all the prestige and grandeur which attaches to those concepts in a Christian society.
The parables and words of Jesus are so powerful that they tend to take hold in the imagination, if they are given sufficient opportunity. This is why even militant atheists such as Richard Dawkins and Carl Sagan often proclaim themselves Christians, in a non-supernatural sense. It explains, too, how even an anti-Christian philosopher such as Friedrich Nietzsche or an anti-clerical author such as James Joyce can draw on Christian themes and imagery so extensively.
The more Jesus is a presence in any society, I believe, the more likely it is that any given person will be drawn to him, and to his Church.
For all these reasons, I am a defender of cultural Christianity. It's not real Christianity, of course, but it's an atmosphere amenable to real Christianity. And its loss is a great loss.