Becker‘s very first sentence sounds suspect:
Combating crime mainly relies on deterrence through punishment of criminals who recognize that there is a chance of being apprehended and convicted-the chances are greater for more serious crimes.
Mainly? What of prevention (locks, alarms, guards and the like), social pressure and economic growth? I’m skeptical, but that’s another argument.
Fundamentally Becker argues that because weapons are more powerful and more available, the putative good guys must be less cautious about attacking suspected bad buys. In other words, 9/11 changed everything, a view which I’ve always thought doubly naive. First, proliferation of massive destructive power is inevitable, and anyone who didn’t think of that before 9/11 just wasn’t thinking. Secondly, and more apropos to this argument, it is not at all clear that lashing out at suspected enemies is a cost minimizing strategy in such an environment.
I just love this gem from Posner, which attempts to dismiss cost-benefit analysis of war:
But the appropriateness of thus discounting future costs is less clear when the issue is averting future costs that are largely nonpecuniary and have national or global impact.
Please! Perhaps the discount rate would be different, but it would exist. Time preference is fundamental to economic analysis, which is certainly not limited to financial concerns. Incredibly disingenuous coming from someone who certainly knows better.
But Posner can’t resist cost-benefit analysis anyway and sets up a scenario in which a preventive attack would, supposedly, be cost-justified:
Suppose there is a probability of .5 that the adversary will attack at some future time, when he has completed a military build up, that the attack will, if resisted with only the victim’s current strength, inflict a cost on the victim of 100, so that the expected cost of the attack is 50 (100 x .5), but that the expected cost can be reduced to 20 if the victim incurs additional defense costs of 15. Suppose further that at an additional cost of only 5, the victim can by a preventive strike today eliminate all possibility of the future attack. Since 5 is less than 35 (the sum of injury and defensive costs if the future enemy attack is not prevented), the preventive war is cost-justified.
This strikes me as a highly unrealistic scenario. Governments invariably overestimate the benefits of their actions and understimate the financial cost of war by a factor of ten. Did the overthrow of Saddam Hussein eliminate the threat of terrorists based in or sponsored by Iraq? Hardly. Given the rose-colored glasses worn by government planners, in Posner’s scenario above I’d expect a preventive attack to cost 50 and not change the expected damage from a terrorist attack. 70 is greater than 35, war is not cost-justified.
Posner makes many more assumptions in an alternative history example:
A historical example that illustrates this analysis is the Nazi reoccupation of the Rhineland area of Germany in 1936, an area that had been demilitarized by the Treaty of Versailles. Had France and Great Britain responded to this treaty violation by invading Germany, in all likelihood Hitler would have been overthrown and World War II averted. (It is unlikely that Japan would have attacked the United States and Great Britain in 1941 had it not thought that Germany would be victorious.) The benefits of preventive war would in that instance have greatly exceeded the costs.
Why would Hitler have been overthrown in all likelihood had France and Great Britain invaded? Unless they were dead set on regime change is isn’t hard to imagine Hitler surviving. We don’t have to look back far to see a dictator surviving an invasion and military defeat — Saddam Hussein in 1991.
Would destroying Hitler have averted World War II, and not only the one we know? Who knows what set of events an invasion of the Rhineland may have set off? It could be now seen as a the beginning of a tragedy that led to a communist revolution in Germany, the ascendancy of still-credible fascism and anti-semitism in France and Great Britain, the inevitable Fascist-Communist worldwide conflict, and the U.S. pulled mightly to adopt one or the other, leading to mass slaughter and the extinction of freedom worldwide. Strange things happen. See World War I.
Hindsight is wonderful, eh? Unfortunately there’s no reason to expect it to be 20-20 unless we hold nearly everything constant. Foresight is even harder. We desperately need tools that provide better estimates of the impact of policy than bogus intellectual handwaving and self-serving bureaucratic guesstimation. Conditional futures, which I’ve mentioned here and here may be one such tool. I don’t think conditional futures is quite the term of art, but see Robin Hanson’s page on policy markets for a good explanation and his pages on the Policy Analysis Market and idea futures for far more in depth treatment.