- I trust the sanity of people who have the most to gain by not engaging in nuclear war. Being king > being dead. And yes, even Kim Jong Il has more to gain by not nuking, and he's as close to insane as we've got. It's in Kim Jong Il's interest for people to think he is crazy - he (and those in power around him) gain nothing, however, by actually engaging in Nuclear War.
- The main argument I've heard for Mutually Assured Destruction (MAD) not being stabilizing: Bernard Lewis, who claimed that the Iran govt was apocalyptic, and saw the certain destruction of nuclear war as an inducement, rather than a deterrent. I spent a good part of last year writing a response for my War on Terror class. My core counter argument was, essentially, that while Ahmadejinehad (and Iran proxy) have a lot to gain through nuclear posturing, and even through the possession of nuclear weapons, they are first and foremost a government. And as a government, things are better for them if they both a) stay in power, and b) stay alive. Religious belief may be strong enough to motivate a terrorist to kill himself on behalf of his community, but very few people are genuinely willing to risk initiating the actual death of their community. Altruistic motives fuel suicide terrorism; if you think your death will benefit the community, you may well do it. But it does not extend far enough to risk the entire community, because nothing is gained by that.
- M.A.D. works precisely because even if the leader has more to gain in a war, and leaders usually have the most to gain, gains in war become impossible w/nuclear second strikes. Were a nuclear nation to initiate war against another nuclear nation, the damages that resulted would be, well, apocalyptic. You'd get two devastated nations, and the cost + time involved in rehabilitating them is certain to be expensive. Not going to war is, in this day and age, always cheaper and the better economic prospect for a nuclear armed nation. Plus, any government that initiates such a war is sure to either die, be deposed, or be greatly reduced in power within minutes.
- Finally: a single person may be irrational (Ahmadejinehad, Kim Jong Il). But a small group of people (say, the rest of the governing bodies in Iran with a special emphasis towards the Supreme Leader, or the bureaucratic elite of the DPRK) errs towards rationality.
- Governments of States, as collections of people with a vested interest in preserving the status quo, are going to be more rational and more restrained that the sum of their parts. They might posture, and they may well pursue nuclear weapons as a deterrent, but actually engaging in nuclear war is not in their interest.
Qualifiers and Postscripts:
Nuclear forensics is valuable, but it isn't as effective a deterrent as MAD. MAD is purely a "between states" thing, and works on the premise of states as rational actors. Since states have a lot to gain by posturing, posturing through nonstate loose cannons is a fancy little risk in this day and age. That said, nuclear forensics still holds promise of making deterrence continue to be relevant, two decades after the cold war.
Security through proliferation? The topic itself came up because a friend made an aside about how giving everyone nuclear weapons was not the path to peace. Another friend interjected that I "might advocate giving all STATES nuclear weapons. Some silly thing about rational actors." So, I then went out and kind of babbled my way through a rough version of the argument you see above. I genuinely trust states rational actors, and I stand by the value of deterrence in a world with nuclear weapons. What I omitted in the above argument but included in my conversation are two fairly important asides:
- The only nation that was nuclear and actively, unilaterally disarmed itself was the apartheid government of South Africa. The reasons for this were multiple - the cold war was ending, South Africa really didn't see a need for itself to be nuclear, and the outgoing government really did not trust the rationality of the people they were handing the reins of power over to. It's an example of disarmament, which is a net win for everyone, through an explicit distrust in the rationality of states, which is probably fair but makes me a sad panda. I'm not sure what relevance this has, beyond being basically a silver bullet counterargument to my stated claims. Seemed worth mentioning, any way.
- Having nuclear weapons protects a single nation while increasing the risk to all other nations, resulting in a net lose of security. This is a macro-scale effect of the SUV phenomenon: if you drive an SUV, you yourself are safer, but every SUV on the roads makes the roads less safe. More nuclear weapons among more states doesn't actually provide much in the way of stability to anyone outside the most recently nuclear state, and greater proliferation comes with a greater risk of loose nukes and nonstate actors using them. For this reason, while I don't begrudge a nation like Iran seeking to protect itself with a nuclear deterrent, I'm really not all that fond of greater proliferation. I understand it, and don't see it as leading to the end of the world, but in absolute terms it's not a good thing.