For the love of science dude, every situation isn't comparable to WWII. Iran isn't Germany. Not remotely close. They aren't going to take over Europe, nor would they nuke anyone unless they want to die very quickly - which would be the inevitable result and they know it. Iran is belligerent, against human rights, anti-semitic, and radical, but do you truly believe they are suicidal? I don't.
Do you have any idea how many people would die if we went to war with them? Iraq's military was in shambles and we lost 4500 of our troops and 100,000+ Iraqis died. Iraq has a population of roughly 33M. Iran has a population of 77M, a way more advanced military, and their mountainous landscapes would provide much better cover for an insurgency.
A military option against Iran would be a truly terrible thing - for tens of thousands of our troops and their loved ones. I don't think you take it completely off the table, but to toss the idea of war around so casually as if the diplomatic option was so beneath our dignity that it would be worth it......I don't see the logic.