Chesterton thought it was a bad idea:
“Whatever else is right, it is utterly wrong to employ the argument that we Europeans must do to savages and Asiatics whatever savages and Asiatics do to us. I have even seen some controversialists use the metaphor, ‘We must fight them with their own weapons.’ Very well; let those controversialists take their metaphor, and take it literally. Let us fight the Soudanese with their own weapons. Their own weapons are large, very clumsy knives, with an occasional old-fashioned gun. Their own weapons are also torture and slavery. If we fight them with torture and slavery, we shall be fighting badly, precisely as if we fought them with clumsy knives and old guns. That is the whole strength of our Christian civilisation, that it does fight with its own weapons and not with other people’s. It is not true that superiority suggests a tit for tat. It is not true that if a small hooligan puts his tongue out at the Lord Chief Justice, the Lord Chief Justice immediately realises that his only chance of maintaining his position is to put his tongue out at the little hooligan. The hooligan may or may not have any respect at all for the Lord Chief Justice: that is a matter which we may contentedly leave as a solemn psychological mystery. But if the hooligan has any respect at all for the Lord Chief Justice, that respect is certainly extended to the Lord Chief Justice entirely because he does not put his tongue out.
“Exactly in the same way the ruder or more sluggish races regard the civilisation of Christendom. If they have any respect for it, it is precisely because it does not use their own coarse and cruel expedients. According to some modern moralists whenever Zulus cut off the heads of dead Englishmen, Englishmen must cut off the heads of dead Zulus. Whenever Arabs or Egyptians constantly use the whip to their slaves, Englishmen must use the whip to their subjects. And on a similar principle (I suppose), whenever an English Admiral has to fight cannibals the English Admiral ought to eat them. However unattractive a menu consisting entirely of barbaric kings may appear to an English gentleman, he must try to sit down to it with an appetite. He must fight the Sandwich Islanders with their own weapons; and their own weapons are knives and forks. But the truth of the matter is, of course, that to do this kind of thing is to break the whole spell of our supremacy. All the mystery of the white man, all the fearful poetry of the white man, so far as it exists in the eyes of these savages, consists in the fact that we do not do such things. The Zulus point at us and say, ‘Observe the advent of these inexplicable demi-gods, these magicians, who do not cut off the noses of their enemies.’ The Soudanese say to each other, ‘This hardy people never flogs its servants; it is superior to the simplest and most obvious human pleasures.’ And the cannibals say, ‘The austere and terrible race, the race that denies itself even boiled missionary, is upon us: let us flee.'” — G. K. Chesterton, Humanitarianism and Strength
If this seems offensive, remember that Chesterton was a man of his time, and so took for granted that cannibalism was bad.
Anyway, it’s counterproductive to fight terrorists with their own weapons. We’ll do better if we fight them with our own weapons. Four other things we should not do:
- Respond to attacks proportionately; this is a variation on fighting with our enemy’s weapons, and it’s a fool’s game. We should instead respond disproportionately. [updated for clarity] If someone beheads an American, we should bomb an oil refinery.
- Lie about Islam. Islam is “false in its claims and pernicious in its moral and political consequences.” Our leaders should not try to ingratiate themselves with middle-eastern fanatics who want us converted or dead, or with their better-dressed apologists in our own country who ultimately want the same thing.
- Give money to our enemies, whether buying stuff from them or giving them “humanitarian aid” so they can buy bullets.
- Reward our enemies and punish our allies, ’cause that’s just stupid.