Consider a different announcement by the British prime minister. What if Blair had said that the world could do with one less nuclear power rather than one more? Britain built a nuclear deterrent to deal with a clear and identifiable threat — Soviet communism. Now that threat is gone, and even though Russia still retains thousands of nuclear warheads, it is simply inconceivable that Moscow would decide to use them against London or any other UK city — whether Britain had the capacity to respond or not. The same is true for all the other established nuclear powers. Therefore, the fundamental reason why Britain has long deployed nuclear weapons has disappeared — and so has the rationale for their modernization.

What if Blair had made clear that although the world remains full of dangers and risks, Britain’s possession of nuclear weapons isn’t going to make Britons any safer? A small British arsenal — or even a big one — will not persuade terrorist from not attacking London nor rogue states from not acquiring nuclear or other weapons of mass destruction.

Blair, of course, said no such thing. Instead of making a persuasive case for why nuclear modernization is in Britain’s interest, he put the onus for his decision on those who argue that Britain should get rid of its weapons — or at least allow the deterrent to whither away by deciding not to modernize the force:

Those who question this decision need to explain why disarmament by the UK would help our security. They would need to prove that such a gesture would change the minds of hardliners and extremists in countries which are developing these nuclear capabilities. They would need to show that terrorists would be less likely to conspire against us with hostile governments because we had given up our nuclear weapons. They would need to argue that the UK would be safer by giving up the deterrent and that our capacity to act would not be constrained by nuclear blackmail by others.

Actually, the onus for making the case should be on Blair and on those who support him. Pray tell, how does a British nuclear arsenal affect the calculus of countries like Iran and North Korea in deciding whether or not to acquire nuclear weapons, given that it hasn’t had much impact so far? Pray tell, how are terrorists bent on suicide operations going to be dissuaded from launching an attack by Britain having 160 nuclear weapons?

And, pray tell, what message does Britain send to all those countries that have decided to forego their own nuclear capability in this uncertain world? If an independent British nuclear deterrent is, as Blair says, “an essential part of our insurance against the uncertainties and risks of the future,” why shouldn’t Germany or Japan or Saudi Arabia or Nigeria or Brazil or all the other countries who have decided to forego nuclear weapons not possess a similar insurance capability? Indeed, it is the message Blair sends to these countries — rather than to those supposedly intimidated or otherwise affected by his decision — that should concern him the most. But it is a concern that apparently never crossed his mind.