I do note that Pape and others point out that 'most' of the suicide attacks in Iraq come from young people recruited from OUTSIDE Iraq...with Saudis being prime candidates.

and for a slightly different view of Robert Pape's work, Carol, you might read this article from a couple weeks ago

I note particularly this comment:

"Research by other scholars backs up this point. David Laitin, a Stanford University expert on civil wars, and Eli Berman, an economist at the University of California at San Diego, have demonstrated that while only 18 percent of the 114 civil wars since 1945 have pitted members of one religious group against another, fully 90 percent of suicide attacks take place in inter-religious conflicts."

This is the phenomenon *I* am noting....and it seems to me that, when religious leaders do not explicitly and strongly condemn hate-based violence, many followers take it as tacit approval.