In all feasibility an attack on Iran would not involve a military invasion and thus there would be no clarification to whether or not air strikes would wipe out their nuclear program...the likely results would be multiple airstrikes over the course of several days which merely delay the Iranians program.
Embargos will not work for a number of reasons; the most prominent being the countries in the international community will economic interests in Iran including Japan, Pakistan, China and Russia will not participate. China and Russia's veto on the UNSC means it is also likely the UN will not participate.
The Europeans are quick to talk tough on Iran but have merely bought the Iranians plenty of time to continue their program (even if they say it was ceased duel use items and indiginous advances in technology allowed it to continue) but are unlikely to back it up militarily. A story to summarize goes like this: during EU3 negotiations with Iran Ahmaninijad was at a UN meeting in NY talking with another Iranian politician and summed up the negotiations as "The Europeans are like dogs...if you kick them they will run away." The Europeans have no intention of militarily striking Iran which makes an American invasion all the more unlikely.
Israel on the other hand is very frightened with Irans progression as Iran constantly threatens Israel's existence and promises its eradication. The question is will Israel strike Iran before negotiations are completed or allow a diplomatic solution. It doesnt help that the Iranians do a great deal of bluffing and are more happy then ever to be in the international spotlight the way they are now.
What is really needed in Iran is a change of leadership and more democratic measures to allow reformists to run and be elected to make Iran more free and less hostile to its neighbors. Unlike Iraq, Iran has a number of democratic institutions in place which are partially but not totally free including parliament and judiciary. If these institutions are freed from the control of the ayatollahs and Revolutionary Guard it is much less likely.
So IMO there may be airstrikes a year or two down the road but not this:
