Judge Richard Posner (appeals judge on the Seventh Circuit, professor at the University of Chicago) says that it’s OK to fight a preventative war if the expected benefits of the war outweigh the expected costs.
Quick reality check, ladies and gentlemen: when was the last time two countries went to war and both countries’ leaders had accurately predicted the costs and benefits? Let’s review the past twenty-five years. The Bush Administration, and every member of Congress who authorized the present invasion of Iraq, underestimated the cost of the occupation. In the previous Gulf War, Saddam Hussein underestimated the likelihood that the US would intervene to protect Kuwait. Slobodan Milosevic underestimated the likelihood that NATO would do anything more than wring its hands over the fate of the Bosnian Muslims. Ariel Sharon underestimated the cost of maintaining a friendly government in Lebanon. Yasser Arafat underestimated the benefit that the Palestinian people would gain from the intifadah.
If calculating the costs and benefits of a fight were as easy as pricing a stock option, then few if any countries would go to war at all. “As you can see from this mathematical proof, our expected benefit from invading you is 500, and our expected cost is only 100.” “By Jove, you’re right! I’ll just advise my government to unconditionally surrender to you now, and save us both a lot of trouble.”
Indeed, when the costs and benefits of a war are clear to everyone involved, there is no war. In 1940, the military forces of Lithuania, Latvia, and Estonia were obviously no match for the Red Army. Therefore, when the Soviets sent in troops to occupy those countries, they met with no resistance.
via Crooked Timber et al.