Of all places, The American Conservative has an interview with an academic (Robert Pape) who studies patterns of "suicide terrorism" as part of his focus on International Security Affairs. Pape's conclusion is that:

The evidence shows that the presence of American troops is clearly the pivotal factor driving suicide terrorism.

And he goes on to lay out a variety of reasonable, data-driven arguments. Here's another exchange from the interview:

TAC: That would seem to run contrary to a view that one heard during the American election campaign, put forth by people who favor Bush’s policy. That is, we need to fight the terrorists over there, so we don’t have to fight them here.

RP: Since suicide terrorism is mainly a response to foreign occupation and not Islamic fundamentalism, the use of heavy military force to transform Muslim societies over there, if you would, is only likely to increase the number of suicide terrorists coming at us.

Since 1990, the United States has stationed tens of thousands of ground troops on the Arabian Peninsula, and that is the main mobilization appeal of Osama bin Laden and al-Qaeda. People who make the argument that it is a good thing to have them attacking us over there are missing that suicide terrorism is not a supply-limited phenomenon where there are just a few hundred around the world willing to do it because they are religious fanatics. It is a demand-driven phenomenon. That is, it is driven by the presence of foreign forces on the territory that the terrorists view as their homeland. The operation in Iraq has stimulated suicide terrorism and has given suicide terrorism a new lease on life.

I disagree strongly with Pape's tactical view that "For us, victory means not sacrificing any of our vital interests while also not having Americans vulnerable to suicide-terrorist attacks," mainly because i think we need to consider sacrificing some of what we seem to see as vital interests. America can't go on pillaging the rest of the world indefinitely, and i think it would be immoral to try. But even if you disagree with his premise, at least he's looking at actual data and trying to draw reasonable inferences from it. If only the Bush Administration would think clearly like this!

i found this link through Bruce Schneier's weblog.