1) Challenge the Islamic world to a public debate on the truth of Christianity vs. Islam
Debating the truth of candidates and religion generally get you nowhere. People can be presented with truth, but it takes time for them to recognize it. And if they were raised a certain way, the chances of that happening can be very slim. What you'd be faced with is still more attacks until you had to take action. It looks like your course of action is listed below.
2) Nuke Mecca, and point to verses in the Koran which say that it will stand forever, and say, “Your God lied, the Koran is the work of man”
Nuking Mecca would instantly make the United States the number one pariah nation on planet earth. We wouldn't have one allie, except perhaps Israel. Even they would have to couch their support or risk being hated even more by every nation right along with us. Every Muslim on the planet would be aiming to kill you and I off, including tens of millions of them within our borders.
Most of our Embassies and consolates around the world would have to be closed in the short term. Many nations would boot us for a period of time. Others would be closed due to verified threats, and the inability to protect them.
Neither of these ideas would pan out. If you think Muslims are going to wilt because we destroyed Mecca, I think you're dreaming. These people aren't rational. Don't expect them to act along rational lines.
If these don't work, what then?
Not really. Many were disillusioned when “Baghdad Bob” turned out to be a bold faced liar. Destroying what the Koran says will stand forever will destroy the faith.
That’s why they hate Israel so much:
1) the Bible says the Jews will return to Israel
2) the Koran says nothing about the Jews returning to Israel
Israel’s presence invalidates the Koran, and validates the Bible. It’s a great witnessing tool.
Nuking Mecca would not make us a pariah nation after “another 9/11”