I have not read every post in this thread, that being said, I would like to make one small point
Should the US bomb Iran, or should the US invade an Island of Iran, then Iran is probably going to take that as an act of war.
What happens in 2 years or so, if the war is still ongoing and Iran succeeds in making 4 or 5 a-bombs. First they test one underground, so the world knows where they stand.
Next Iran wants an end to the war and an end to sanctions, otherwise is goes further. What happens is Iran smuggles a few a-bombs into US cities via Canada, Mexico, semi-submersible rendevousing with a fishing boat. A container is a container ship that docks in a US port. What happens if they lob a long range artillery shell into a US military base in Kuwait? Ever heard of nuclear artillery?
All these things are not purely military matters to stop, they are intelligence matters. A suitcase bomb is the size of a suitcase. Think you can stop all of them? The US is trying to stop drugs getting into its country, how much do they stop, maybe half? maybe less.
I was watching the TV show cops the other day. There was a Mexican caught trying to get into the US. Big deal you say. But the thing is that he had a job and a family in teh US. It had been so easy for him to travel back and forth, that he would regulary go visit his family in Mexico before coming back across the border. They would wait for a day with lots of fog, the helicopters couldn't see anything, sure the ground patrols get a few, but how many ..60 percent?
What happens is Iranians fly a cessna across the border and drop a suitcase a-bomb at night into a lake, to be collected weeks or months later. Think you are likely to stop that? Iranians are going to blend into the populace of the US a lot better than North Koreans, simply via their looks. No doubt they would be exceptionally well trained. Years of training for one single mission, infiltrate the US and carry out your instructions.
How many years have we heard stories of Columbians running semi-submersibles to meet small boats off the US coast, Crewed be 3 or 4, but these days unmanned and programmed by GPS. They were running for years before they even interdicted the first one.
What happens if the bomb is on a sailing yacht, that meets with a fishing boat 15 miles out to sea at night, with good intelligence you might stop it, militarily is very very difficult. Are you going to search every yacht sailing to the US at 200 miles out?
There are more ways of deploying an a-bomb that via an ICBM.
You might be able to stop most of them, but in no ways are you going to stop them all. Hey the Iranians might be nice, they might just use their suitcase bomb to blow up a fleet base, or NSA headquarters, and not detonate it in the middle of Manhattan.
What is your stop for that? The only shot you have in your locker is say to the Iranians, if you detonate an a-bomb we will nuke you all. What are you going to do, kill 75 million people? What happens next? Any Iranian agents will no doubt use their dozen a-bombs and blow up a dozen cities, After that no problem, they dont have any a-bombs left.... hey no big deal.
My point is that if you bomb Iran, that is an act of war. If you declare war on someone you cant expect them to play nice.