How so? Why would Iran ever want to use a nuke against us? Because we're Christians? Well Russia is Christian, why aren't they attacking Iran to keep them from getting a nuke?
This fear mongering over Iran's nuclear program isn't grounded in logic or reason. It is entirely fueled by bigotry and ignorance. If we were to stop meddling in the Middle East and just focus on our homeland Iran would pay us no mind. The only reason Iran hates us is because we're the ones who have been messing with them.
If we weren't meddling in their affairs for nearly a century they would have a relationship with us like they do most other non-Islamic countries. The idea they hate us for no reason and will irrationally try to attack us the second they get a nuclear bomb is not grounded in logic or reason but is instead based on nothing but ignorance and hate.