Foreign Policy and Suicide Terrorism

It is a popular argument among libertarians - suicide attacks and terrorism are endogenous to foreign occupation. The USS Cole was attacked, the logic goes, because it was there - no one comes here and blows up our ships in our docks. I've always thought the logic was very compelling, but a few years ago when I fully transformed into a cynic who requires evidence for my beliefs, I started to wonder if it was actually empirically true. Did variation in foreign occupation cause variation in suicide terrorism? Now, a new forthcoming paper in the American Political Science Review (which is a journal that may or may not be great) argues that the evidence for this is weak. Here's the criticism in a nutshell:

In short, they argue, the problem is this. To know whether X causes suicide terrorism, we need to know how the propensity to use suicide terrorism varies with X. That is, we not only need data on when suicide terrorism occurs, we need data on when suicide terrorism does not occur — i.e., when groups choose other tactics besides suicide terrorism. Analyzing only instances when suicide terrorism occurred is not sufficient.