Donald Trump And The Emperor Theodosius: What The Church Got Wrong On February 27, AD 380

There's a very strong argument for saying that today marks the day in history when things began to go very, very wrong for the Christian Church. It's the day it sold its soul for political power, and that deal with the devil has been a source of corruption and conflict ever since. In the world of Donald Trump, the consequences of that diabolical transaction are on public view once again.

For today is the anniversary of the Edict of Thessalonica in AD 380. The Roman Emperor Theodosius, with his co-emperors Gratian and Valentian II, irritated by doctrinal squabbles between Arians who denied the divinity of Christ and Nicenes who believed in the Trinity, decided to come down firmly on the orthodox Nicene side. From now on, it would be the Christianity of the Council of Nicea that prevailed. Furthermore: 'As for the others, since, in our judgment they are foolish madmen, we decree that they shall be branded with the ignominious name of heretics, and shall not presume to give to their conventicles the name of churches. They will suffer in the first place the chastisement of the divine condemnation and in the second the punishment of our authority which in accordance with the will of Heaven we shall decide to inflict.'

You see what's happening here? For the first time, the Church was established by law. An all-powerful totalitarian state was decreeing that Christianity – and a particular brand of Christianity, at that – was true. And Christianity has never quite got over that mis-step, when it was shown all the kingdoms of the world and promised all their power and authority, on one condition (Luke 4:6) – and made the wrong choice.

It's easy to see how it happened; here was a godly emperor (more or less) offering something that was obviously desirable (making everyone Christians). What's not to like? But that unholy marriage of secular and sacred authority was always wrong. Yes, in countries with an established state church, it has often been able to moderate the worst excesses of their rulers – and St Ambrose famously stood up to Theodosius over the massacre he instigated at Thessalonica. But it's also been fatally compromised when its leaders have ended up as spokesman for ideologies that have nothing to do with the gospel and everything to do with maintaining power.

The Church is not about secular power. It's not coterminous with the state. To be a Christian it's not enough to be born in a particular country. You have to choose to follow a particular person. And what happened on February 27, 380, set the trend for what happened in many other places in many other eras: freedom of religion was annulled, explicitly or implicitly, in the interests of social cohesion or political expediency. Europe's rulers said, 'You have to be a Christian, and you have to be our kind of Christian.'

What's happening in parts of the Western world today is a reflection of that religious imperialism. In Hungary and Poland, politicians appeal to their countries' Christian roots and call for resistance to an influx of Muslims. In America, the support of evangelical Protestants was a major factor in Donald Trump's election as president – and many of these evangelicals are driven by a belief that America is Christian, and that recent godless governments have been undermining its fundamental character. That's why Trump's attempt to ban Muslims and refugees plays so well: the power of the state is supporting the institution of Christianity by eliminating its rivals.

There's another way of doing Church, though. It's quieter and a lot less dramatic. It doesn't involve strident calls for Christian rights. It doesn't do Christian flags or banners. It doesn't seek to pull the levers of power, though it will take up civic responsibilities willingly enough. It works through small gatherings of ordinary people, who are led by a desire to be Christ-like disciples.

These people don't seek to impose their views on others – not because they aren't confident of them, but because they know it would be pointless. They don't want people to behave in a moral way because they have to, they want them to do it because they want to. They know that one of the greatest gifts of God is freedom to choose.

They know Theodosius got it wrong – and the Church gets it wrong when it lines itself up with the powerful instead of siding with the poor and insignificant. You cannot impose faith; you can only offer it. And evangelicals in America may yet pay a high price for identifying their own interests with that of a secular ruler who they believe will give them what they want.

Follow Mark Woods on Twitter: @RevMarkWoods