Young Islamist gunmen from Hamas and their nationalist Fatah counterparts have until recently been killing each other in the streets of Gaza and the West Bank. Granted there are political and cultural explanations for such violent behavior. But the role of demographics - specifically the vast numbers of young men in the Palestinian Authority - must also be factored in if one wants a better understanding of events in the Arab-Israel conflict. Political scientist Samuel Huntington, author of The Clash of Civilizations, has argued that this huge reservoir of young men aged 15-30 provides a natural pool of instability and...