The new issue of The Economist has several articles about the possibility of a U.S./Iran war.
The ponderous process of adopting a new sanctions resolution at the UN will probably get under way next month. But Iran is already feeling a much sharper pinch from financial sanctions that do not require further UN approval. Operating under the United States Patriot Act, as well as on the basis of a presidential directive adopted in 2005 to target the funds of proliferators, officials from America's Treasury Department have been criss-crossing the globe to persuade governments and banks to curb their business with Iran.
As a result, Iran is finding it increasingly expensive to borrow money. Foreign government-backed credits are getting harder to come by; Japan is among countries that have scaled back their plans to invest in Iran's oil and gas industries. Even legitimate businesses are suffering, as foreign banks find it hard to be certain that the transactions they handle are not being diverted, for nefarious purposes, through Iran's network of front companies. All dollar exchanges, including small transfers for private individuals, have become extremely complicated, and it is very hard to use a credit card to buy online from inside Iran. Already capital is fleeing the country, much of it reportedly ending up in Dubai. ...
Iran has buried many of its nuclear facilities deep underground and has carefully dispersed them, so there is no single target. Senior Israeli security officials argue that, if there is to be military action, it should be carried out by the United States.
Arguably, the best opportunity for a surgical strike has already passed. The Isfahan conversion plant, which produces uranium hexafluoride (UF6, the uranium compound that is passed as a gas into the centrifuges to be enriched), is above ground and vulnerable to attack. It was the first part of the nuclear programme to be restarted by Iran in 2004, and has since produced about 250 tonnes of UF6—enough for 30-50 atomic bombs. But it is now thought to be stored in underground bunkers, much harder to hit.
Another choke-point is the Natanz enrichment facility; but this is buried some 15-18 metres under soil and concrete, and modern bunker-busting bombs might not be able to destroy it. The use of ground forces to secure the area long enough to do the job would be highly risky; the use of a low-yield nuclear weapon, as some suggest, might work physically but is hardly conscionable politically—or morally.