Our newish and welcomed commenter Francis W. Porretto quoth essays from his excellent blog, Eternity Road, here and here as to the nature of Islam and particularly Islamicism. (Those quoted in turn include at least one actual Muslim.)
Mr. Porretto illustrates why Islam, conceptually and historically, is a rare---indeed unique--- bird. It is both a religion and a politics---a comprehensive divine plan for mankind, according to its adherents. Just ask them. We appreciate the contributions of our other commenters, but one cannot discuss Islam and its relation to the current crisis without actually learning of Islam, and so we must. It is not the Kiwanis Club. We, the children of Rousseau (and the materialist Marx, let's face it), have been under the impression that one size fits all.
As human truth, that may be true at its most basic, and we hope it is, that human nature is universal and not, say, racial and particular. But as Aristotle points out (and even Rousseau would admit), acculturation and habit help create the human being, too. There has been a concentrated effort in the Muslim world over the last 50 years, both Sunni (the Saudis' evangelization of Wahhabism) and Sh'ia (the Iranian Revolution), to inculcate the worldview that I attempted to describe in my original essay below, if we can remember back that far.
(I'm fascinated by the etymology of the word "inculcate"---to put your foot on someone's throat. I believe it's accurate and probative in this case.)
It cannot be merely the luck of the draw that there were no Hindus arrested recently with a grand plot to bring down 10 airliners---Pakistani and Indian alike suffered identical indignities at the hands of the British raj. And the history of the United States is full of visiting like indignities on Central and South America, yet still they don't conspire to mass murder to any observable degree. Even Hugo Chávez just wants to tweak our noses (and perhaps we have it coming), not kill our wives and children.
The challenge of the present age is not a question of politics or economics---the answer must lie elsewhere. We must begin to look for it.