"Islam is the enemy. Mecca is its home."
"I'm more hoping that the threat that it could happen will give pause to terrorists."
Mecca isn't home in a military sense. If we are nuked, "hoping" and "giving pause" are poor strategies. You take out your enemy and your enemy's weapons; you don't strike at them simply hoping they'll submit or change their minds...you strike them emphatically to keep them from ever striking you again. You strike them to keep yourself alive. While one of our cities is smoking and radioactive it would be IMHO immoral simply to nuke Mecca because it guarantees nothing and keeps us at terrible risk. Terrorists are empowered by the states that sponsor them, that arm them...this is where we strike. What is Islam militarily if no nation wants anything to do with Islamic terrorists? States who sponsor terrorists should know that if we are hit with a nuke, they in turn will ALL be hit with nukes regardless of where culpability lies....MAD. I really doubt Syria, for example, will stop its sponsorship of terrorism because Mecca is no more.