Andrew
Your point is very logical and it hits at the heart of the issues we face. Can our constitution with stand a religion such as Islam? I am not convinced it can if Islam becomes then majority. The death of people that live in the proximity of Mecca for changing their religious beliefs is a reality. The killings are to fulfill the teachings of the Koran. So can our laws in the US protect us from Islamic extremists? I wish I had the answer but I do not.

You say "The law of Islam is what calls for the death of a Muslim who leaves the Islamic faith for Christianity or Judiaism or whatever", yet not one Muslim has ever been put to death for changing religions in America. So the country's laws outweigh what the religion calls for...get it?