In his Christmas message, the Bishop of Durham, Dr Tom Wright, urges us to stand up for the homeless, poverty-striken asylum seeker who died with a price on his head.

"DRIVING through the West Highlands last summer, we passed a snack bar with the name The Jaco-Bite. Worth a smile, it made me think: yesterday's radical political statement becomes today's tourist trivia. Not that long ago, people fought and died in the Jacobite rebellions about who was the true king. Now the word that stirred the blood is simply stirring the coffee.

Something similar has happened to Christmas. The Bible tells the story of the birth of the rightful king, coming unexpectedly to claim his throne. But someone else was on it, watching his back, ready to lash out at potential rivals.

What have we done with that explosive story? We've domesticated it. Romantic Christmas card scenes of Wise Men riding into the sunset are the tourist trivia, our way of defusing an awkward, threatening claim. We don't just need to "put Christ back into Christmas", as people often say. The Christmas story is about a lion, but we've often pretended it was about a pussy-cat. We need to get back to the lion.

Think for a moment of Middle-Eastern power politics, ancient and modern. Overshadowing the story of Jesus' birth was the biggest warlord in the region and, behind him, the single global superpower of the day. Rome liked to rule through local thugs (it was cheaper, and someone else picked up the aggro). Not that Herod the Great minded. He was the fiercest dog on the block and didn't care who knew it. Rome had even given him the coveted title, King of the Jews.

Great title, wrong man. We know a lot about Herod from the historians of his day. They were fascinated by his nifty political footwork, his energetic building programmes, and his paranoid brutality even against his own family when he thought they were plotting against him. Not the sort of man to take kindly to the rumour of a new-born king.

Against this background, the story of Jesus' birth reads like the first-century equivalent of the Jacobite rebellion. Remember the old song: "Carry the lad that's born to be King/Over the sea to Skye"? The point of the Christmas message is that Jesus is "born to be king". King of the Jews, of course; Messiah (or Christ) was the word for the "anointed"' king who would come to set Israel free. But Jews of the day believed - and the early Christians eagerly took this up - that when the Messiah appeared he would be king, not only of the Jews, but of the whole world. A rival, in other words, not just to Herod, but to Caesar himself.

That's why the angels sang at his birth, and it's why people ought to sing at Christmas now. We all know the world is not running according to plan; we celebrate the one who came to change it all, to put it all to rights, to deal with the problem at the root - and then to return at last to finish the job, and usher in the final reign of truth, justice and peace.

This is why the modern world has been so keen to do with this explosive story what the tourist trade does with the Jacobite rebellions. For the last 200 years we have been telling ourselves that religion in general, Christianity in particular, and Christmas especially, is all a private matter. It's all about "my spirituality", about feeling good inside, a kind of mystical self-help technique.

It isn't, in other words (so we have implied), about the public world, the world of empires and local councils, of bad laws and unjust taxes, of asylum seekers and prostitutes, of unpaid debts and unexplained death. It's an escape from all that, we have been told. And the way we "do" Christmas reinforces this message. A nice party for the children (or perhaps a seedy one for the grown-ups); not something to be allowed out into the real world of real lives and real decisions.

People sometimes say the problem with Christmas is that it's too commercialised. That may be true. But the point is this: once the real meaning of Jesus' birth has been turned into private religion, irrelevant to the world outside, the only "outside reality" you're left with is shopping. The antidote isn't to make Christmas more "religious", if by that you mean "more about my private spirituality". That's important, but the spirituality which sustained the early Christians was their faith that in Jesus the living God had come to claim his rightful kingship, not over some other world but precisely over this one.

For them, that meant celebrating Jesus' kingly rule under the noses of the power-brokers of the day, living as though he was in charge and not them. As a result, his power flowed through them: lives were changed, people were healed, communities were transformed. They often got into trouble for it, of course, but they didn't mind too much. For us, it ought to mean celebrating Christmas for all it's worth: not just in church and at home, but out on the street, in the way we organise our towns and cities, in the way we care for old people and children, in creating a world where the vulnerable are welcomed and those at the bottom of the heap are given the helping hand they need. Do it in the name of Jesus and see what happens.

You will find (as I do when I say all this, whether in the pub or in the House of Lords), that today's Herods and Caesars don't like it. Today's power-brokers don't like being reminded that religion remains a key dimension of real life. Secularism fights back angrily to keep control of the territory it has recently gained. Our present global superpower doesn't like people suggesting that the gospel of Jesus - which some American leaders claim to be following - calls into question the deadly combination of money and violence which has driven their Middle Eastern policy, just as it did that of Rome.

For too long we have been content with what the Americans themselves would call "'Christianity-lite", a gospel which provides a soothing personal message, a hot drink by a log fire on a chilly evening. It's time to get out there and challenge the cold and the darkness: to celebrate the rule of the Prince of Peace under the noses of the warlords.

Christmas is all about singing the praises of the baby of Bethlehem. But, as we do so, we must remind ourselves that he was born in homeless poverty; that his first journey was to seek asylum; and that he lived and eventually died with a price on his head, the price of being the world's true king. It's time to re-start the rebellion, to un-domesticate the tradition, and to follow this Jesus for the rest of the year, not just at Christmas, as the one who can and will rescue and transform individuals and society alike."