They wouldn't be able to. I'd imagine if we occupy the Middle East it wold be split up into occupying countries who helped to defeat them (US occupies one part, France another, Russia another, etc) that way the whole world could enforce peace and any sort of "grudge" would go away

Youre not going to completely erase them fom existance. Its not possible. Thats why there are still KKK and [url=http://www.wikipedia.org/wiki/Godwin%27s_law]-godwinslaw!-[/url] sects across the world. You really dont want that kind of thing 100 years from now, especially with radicals like isis.