Jonah Goldberg had a post yesterday wondering if we shouldn't be doing more to prevent the possibility of an earth-destroying asteroid collision. I think we should. The odds of such an impact event in any given year are low, but not really all that low, and the downside consequences would be terrible. Then, as is all-too-often the case, he follows up by quoting an email from a dumb reader complaining about Ron Suskind's book The One Percent Doctrine:
The book knocked VP Cheney for saying that even a 1% chance of terrorists getting nuclear weapons merits serious US action to stop them. But multiplying the 1% by the severity of a nuclear terrorist attack in an American city makes Cheney's statement quite reasonable. Not how it played in much of the press, though.
First, a basic note on probabilities. It's quite right to say that faced with the possibility of a Very Bad Outcome we should take the VBO seriously even if the VBO is unlikely. Cheney's actual doctrine, however, was that faced with a one percent risk of a nuclear terrorist attack against an American city, we should respond as we would were such an attack a certainty. This is obviously daft. If there's a one percent probability of 1 million people dying, the expected value is that 10,000 people will die. If, conversely, there's a 100 percent probability of 1 million people dying, the expected value is that 1 million people will die. The idea that we should treat those values as if they were the same is crazy.
In the specific case of asteroids versus invading Iraq, though, the more salient difference is the downside risks of action. Cheney's doctrine, as he operationalized it, involved simply assuming that inaction courted risk whereas action did not. That, again, is crazy. The risk of spending more money tracking asteroids and starting a pilot research program to study how you might blow them up is that some money might get wasted if your research proves useless or if no asteroids come. The risk of invading Iraq is that hundreds of thousands of people will die, America will fail to achieve critical mission objectives in Iraq, America's international alliance system will end up in tatters, and, generally speaking, the United States will find itself retreating on all major foreign policy fronts. That's the trouble with starting speculative wars -- they're quite likely to go badly awry.