My guess is that Iran probably has two parallell development programs.
One for building ordinary power producing reactors.
One for developing nuclear weapons.

Both programs can benefit from enrichment plants, fuel manufacturing plants and share some expertese.

Iran could back down by importing enriched fuel for their power producing reactors. Not running their own enrichment and fuel plants removes the ability to make highly enriched uranium that directly can be used in nuclear weapons and fuel to small specialized hidden nuclear plants optimised for producing plutonium.

The problem is that it is possible to hide most of the military nuclear program  and to have most of the equipment underground wich makes it much harder to attack.

If aerial bombardment is contempakted as a tool for removing the Iranian nuclear program it gives bad choices.

1. Bombing the obvious civilian powerplants.
Does not help, makes the Iranians mad, shows that USA is a bad country.

2. Bomb the hidden facilities with conventional weapons.
Will probably not be enough, makes the Iranians mad, will be applauded by manny.

3. Bomb the hidden facilitiss with nuclear weapons.
Will probably work if you hit enough of them, makes everybody mad.

4. Bad Iranian planning leaves key facilities out in the open.
Makes Iranians mad and only makes other people realy mad if the only soft spot left was to take out the qualified workforce  including their neighbourhood.

They only good outcome is if internal opposition makes Iran more democratic  and other countries are allowed to inspect that they indeed only run a nuclear power program. If they liberalise seriously it even removes them as a threath even if they do build nuclear weapons. But that will probably take generations.

The nightmare scenario is of mullas afraid of change initiates a war on USA or Israel and use a beginning defeat as an excuse to use nuclear wepons on large soft partly military tagets like ports or airfields.

Dave's excellent post does bear out the fact that Iran's desire to develop nuclear capacity for peaceful purposes of power generation is eminently justifiable by the hard scientific facts.  Nevertheless, it probably is true (in my opinion, anyhow) that Iran is concealing an ulterior motive of acquiring nuclear weapons capabilities also.  Now this deceit on Iran's part is arguably blameworthy (I would argue that it is; as a lover of truth, I would say that deliberately propagating falsehood is always wrong).  But who can justly blame the Iranians for wanting nuclear capabilities as a means of self-defence against manifest US tendencies to engage in unprovoked aggression against other nations?