John Quincy Adams was right on the mark! A better analysis cannot be provided.
One thing many people forget is exactly how long this war has been going on: since the very moment of Mohammed's "visions."
Prodigal Son made some interesting points on another thread. He said that the secret of its longevity is that it does not have one particular leader - its clergy are its leaders, especially those descended from Mohammed, and they are dispersed, as he put it, like "nodes." Taking one or more of them out won't bring down the whole "network." However, the biggest vulnerability of Islam is that it is a geographical religion. That is, if Mecca and Medina were suddenly removed from the face of the earth, Islam would immediately cease to exist. Interesting points.