Without a reasonable probability of success at preventing the development of an Iranian bomb, an attack on their facilities could not be carried out with the right intention, even if the cause is just. It would merely be an act of frustration and anger, not genuinely ordered to the defense of innocent life.Probability of success and right intention, though not rigorously bound, are certainly related in practice. There is a sense in which we might judge a decision to act irrational when the action is expected to fail. If this is true much of the time in war, then it seems valid to claim that such an action is probably motivated by something other than a just cause.
However, this relationship isn't rigorous because there really isn't a contradiction. Since Koons' probability of success doesn't begin and end at 0% (he qualifies the probability required as "reasonable"), war being conducted on a long shot would violate the criterion. If what a nation has to gain (or avoid losing) is so valuable that they are willing to take action with a low probability of success, there would be no barrier to meeting the right intention criteria while violating Koons' probability of success. Since Koons is talking about the Iran conflict specifically here, we can't assess this statement as a problem in his formulation of Just War Theory.1
The rest of Koons' discussion of probability of success is a problem.
Because of Iran’s anticipation of an American or Israeli attack on its facilities, it has hardened the sites to an extraordinary, perhaps even unprecedented, extent.Speculation like this doesn't seem appropriate. Koons can't expect us to trust a philosophy professor's assessment of the effectiveness of bunker buster bombs on particular facilities in Iran over that of the US military. This is an important consideration in the decision to strike Iran, but it is something Koons can't possibly assess himself. Perhaps Koons is admitting this, as he next seems to cede the possibility of success.
Even if an attack were entirely successful at destroying one or more critical sites, the most that could be reasonably hoped for is to delay Iran’s acquisition of nuclear weapons for a few years. Wouldn’t such a delay count as a “success”?Yes, it would. All Koons seems to be saying here is that short of regime change, there is no reason to believe they won't start over, even if all of their current capacity is destroyed. It is clearly preferable to delay the kind of atrocity the US and Israel are worried about if the alternative is allowing it to happen now. There is no sense in which the United States and Israel wouldn't consider this a success.
From here Koons temporarily abandons probability of success.
It’s true that we could be justified in thwarting an imminent attack now, even if doing so wouldn't prevent all future acts of aggression. However, in this case, there is no specific attack that we would be thwarting: we would be merely postponing the acquisition of the means for an attack, and such mere postponement cannot justify the intentional killing of Iranians.Koons is making two distinctions here. The first is between imminent attack and the means of attack. The second is between a permanent solution to a problem and a postponement of the problem to a later date. While the first distinction is morally relevant in general, it is neutralized by the premise of Koons' argument.
I will assume... that there is a significant likelihood that Iran would either use these weapons directly against the United States or Israel, or give them to hostile terrorist groups such as Hamas or Hezbollah.The second distinction, between a problem eliminated and a problem postponed, isn't very convincing. It is silly to claim that self defense should be abandoned because it may not prevent future attacks. Surviving in the meantime is a just cause. Additionally, postponing a problem provides additional opportunity to find a permanent solution. It is entirely possible that Iran would never redevelop a nuclear capability, whether because of international pressure, regime change, or further military conflict.
Koons may actually be claiming that the lack of a literally imminent (not just firmly intended) threat is enough to disqualify military action. If this is the reasoning he wants to follow, it seems strange to introduce it during the discussion of probability of success, the last item on his list of Just War Theory criteria. He is clearly identifying a challenge to just cause, the very first criterion. By merely implying such an objection, Koons avoids having to explain his moral claim.
Part V will summarize the points I have made so far and wrap up my critique of Koons' article.
1. I expect that more traditional formulations of Just War Theory find some way of normalizing the requirements of probability of success to the value of the success, such that an existential threat would require only a small probability of success to oppose, whereas some minor issue barely worthy of war would require a high probability of success to be just.