However, you stated we have people everywhere. To the degree our having personnel on the ground does serve as a shield for the locals against our use of nukes, but intriguingly Middle Easterners have elected to keep their two most culturally significant cities completely unguarded.
This leaves us few real targets.
No doubt we would need to withdraw our personnel from the area before retaliating for a WMD attack. On the other hand, they've already mounted a WMD attack against us and all our government has done is seek to cast the blame elsewhere.
This means they are probably safe from any meaningful US retaliation ~ even if they wiped out the NYC subway system and all the riders someday.
we aren't going to nuke a city like Mecca UNLESS the attack came from there.
I know someone will say "well they're islamic so it came from there" but no one will see it that way so it's unrealistic to say so.
Damascus isn't stupid enough to go through with anything like that unless they think they can win.
But they probably ALSO know that anything that gets traced back to them means instant regime change. They aren't THAT stupid, only Saddam was.
We won't go strategic nuke unless someone big (Iran) hits us. If it's AQ, we will use "smaller" nukes.