There are no moderate muslims. There are only practicing muslims and people who pretend to practice islam because it promotes a longer life. The koran demands that sharia law be forced on the entire world. Period.
The growth of islam is much more extensive than most people, even on Freeper, understand. For example a couple of friends just returned from Kenya and told me the Saudi's are providing free clean water and electricity to much of the country. The catch is you can't use it unless you convert to islam. Lots of Kenyans are 'converting' out of desperation but the interesting thing is that after attending mosque for some time the conversions become real. islam is seductive. You are part of a big, powerful group that god himself has given permission to be in power. You get authority. You get to abuse non-believers. And the supreme moral force in the universe says it is ok. Over 40 countries around the world, that are not now considered part of the muslim world, are rapidly converting. This is world war.
If the threat was credible (destruction of 'holy sites') it would act as a strong deterrent in my opinion. What do you suggest as an alternative? Pretend you are the President. What is your response going to be if Houston is nuked tomorrow?
I guess if I was POTUS I would threaten retaliation on mecca but my actual response might be directed against military and infrastructure - at least at first. Unfortunately that is complicated by the fact that destroying ME oil production would triple or more oil prices and would lead to a severe world wide recession. You could occupy the major oil fields instead but that would really get Russia, China, India, and even Europe really excited. No easy choices here. I'm glad I'm not the next President.
Quickly building several hundred nuclear power plants and converting to hydrogen powered transportation would certainly be helpful.
My response would be to VIOLATE the airspace and territorial sovereignty of the nations where there are known Al-Quaida strongholds and ANNIHILATE them. Remember the song by Martha & The Vandellas “Nowhere To Run”. Our B-2s and F-22s would be very, VERY, V-E-R-Y, B-U-S-Y ! ! ! Al-Quaida stronghold one day SANDBOX the next ! ! !