The majority of the Islamic terrorists (gunmen, suicide bombers, helpers of all sorts) come from madrassas (Islamic schools). Such schools are found all over the Islamic world, but the ones that produce the most terrorists are those that teach a conservative form of Islam, usually one that justifies militant Islam, hatred of non-Moslems and a favorable attitude towards Islamic radicalism. There are probably fewer than five million kids attending these conservative madrassas. But these schools turn out thousands of potential terrorists each year.
This is why it is a long war. Ultimately, we need to get the Islamic world to reject these incubators of hate.
As we've learned, it takes a child twisted by madrassas to raze a village.