CANON Nigel Biggar reproached me for going by the Telegraph’s description of his support for the plan to send asylum-seekers to Rwanda (16 December); so I downloaded and read the Policy Exchange pamphlet on the subject. I also re-read Matthew Parris’s defence of the Rwanda proposal in a recent Times column, because he is someone I have liked and admired ever since we were colleagues, or rivals, in about 1990.

The argument in favour has three main pillars. The first is that every government has a right — and, in fact, a moral duty — to control its own borders. In extreme cases, it ceases to function as a government if it cannot. The second is that there are more refugees and more misery in the world than we can possibly hope to tackle. We have to choose whom we can help and that means declining to help some deserving cases.

The third is that the people who cross the Channel are not among the most deserving cases. Only one fifth of them are girls or women. They are not destitute, since they can pay the people-smugglers. Finally, as Canon Biggar puts it, “the migrants attempting to cross the Channel are not currently fleeing ‘war, famine, and oppression’ in Eritrea, Syria, Iran, or Afghanistan (let alone in peaceful Albania). They are leaving France — peaceful, prosperous, and liberal.” In other words, none of them are really refugees, and we have no obligations towards them at all.

THIS all adds up to a strong argument, which would be stronger still if anyone could be found to make it with a straight face.

For a start, it omits entirely the political background against which these justifications are needed. Mr Parris, to his credit, acknowledges and is revolted by the explicit rationale of Policy Exchange, which is to find a vote-winning policy for a Conservative Party threatened with annihilation from both Left and Right. The leading Christian thinkers whom the think tank commissioned (and presumably paid) prefer an Olympian stance. They are concerned only with the morality of the project.

But you cannot ignore an inadmissible axiom of British politics: that no one can win a decent majority against the active opposition of the xenophobic and racist element of the electorate. This segment of the electorate is not by any means a majority, but, when roused, it has a blocking veto. See under Brexit.

The second unspeakable background fact is that the justice system, in general and the Home Office, in particular, are now broken. You can blame lefty lawyers, Conservative underfunding, or even the European Convention on Human Rights, but the outcome is always the same. The prisons are a disgrace, the court system is crippled by shortages and delays, and the police are overwhelmed. When Something Must Be Done, it must be something possible to do, and, if you want the Home Office to do it, it had better be as simple as herding refugees on to an aeroplane.

This simple policy is not only meant to send a signal to Conservative voters who might be tempted to vote Labour. It is justified, not least by the leading Christian thinkers, because it will also send a signal to the people who might otherwise try to cross the Channel. It has to be both “firmly deterrent” and “Not lacking in care and compassion”, to quote Canon Biggar again. Well, which? You can’t have both.

Deportation to Rwanda is a deterrent if — and only if — the conditions there are very much worse than either living in a French shanty town or rotting in a British detention centre. Remember, the assumption is that Rwanda will imprison the migrants as soon as they arrive, and that imprisonment will, for most, be a sentence ranging from indeterminate to life in miserable conditions. This is what the Australian policy amounted to — and it worked. Nothing less will function as a credible deterrent. The policy has to be seen to be brutal to work for either of its intended audiences. Screams of outrage from archbishops are a necessary element of success.

Perhaps the leading Christian thinkers are simply all Malthusians — and the question that the Revd Thomas Malthus asks us is not whether his doctrine is repulsive, but whether it is true. Must almost every attempt to alleviate the misery of the unwanted and unneeded poor end up making things worse for everyone?

AND so to happier things. There was a comfortable discussion in The Spectator between Robert Harris and Tom Holland, partly to plug Harris’s latest book, Act of Oblivion (Hutchinson Heinemann), which deals with Puritans (Features, Books, 25 November). The pair of them come across as wonderfully Anglican in their slightly bewildered benevolence: “I’m struck by the similarity of [Cicero’s] philosophy to the message of Christianity: the good life is the life of helping others and doing good,” Harris says. “That’s the only way to peace, and that’s the only way to immortality, to a settled feeling of not being afraid of death. If you live a life like Caesar, he thinks his is a wretched life.”

Is that really the message of Christmas? Surely Christianity implies something both more wonderful and more terrible.