Here's just my two cents. Islam believes that it is the infallible word of God, unchangeable, eternal. However, in a nuclear exchange between the infidels and Islam, what would happen if nukes obliterated Mecca and Medina? How can you go to hajj when the site is now a crater in the desert? (Sure, you could go to the site - but all the obligations that you have to do under Islamic tradition during hajj wouldn't be possible.) That would seriously crimp the Islamic belief system.
Another possibility comes from the "us and them" approach in Islam. For the first few centuries of its existance, much of the Islamic expansion took place against tribal chiefs or empires that were old and exhausted. The West may be long in the tooth (at least the Western European wing), but I wouldn't say that the Chinese, Australians, Japanese, Koreans, Indians, or Americans are about just roll over and become Islamized, even after a nuclear exchange. In fact, I could easily see a nastier response from those attacked that could be horrific.
One last thought: this is a joke that circulated around 9-11. The Saudi minister was in Washington talking to President Bush. The minister said that he had seen many things, but he had one question. "Why is it on your television show 'Star Trek' the starships have Russians, Africans, Asians, Americans... people from all over the world, but no Arabs?" The president leans over, smiles, and says, "Well, that's because 'Star Trek' takes place in the future."
I think I'll pass that one along.
I recommend sick jokes at the expanses of Arabs are unproductive. Better to challenge our Muslim participants with the teachings of Jesus such as it is not our hands that are unclean if unwashed before rituals but what comes out of the heart at makes us unclean before God(indeed separates us from God without the grace of Jesus Christ rejected by Islam. These can engage our Muslim aqquaintances/friends to think about their faith and how it compares with the teachings of Jesus (Isa)
Tommy