There seem to have been some pretty effective covert operations against their nuclear weapons program so far: Stuxnet disrupted their uranium enrichment process significantly, it seems, although of course Iran doesn't volunteer details, and there have been several suspicious "accidents" lately: things connected with the illegal weapons program seem to have a strange habit of exploding randomly. The trouble is, these are really just delaying tactics: one way or another, someone will have to disarm Iran, maybe by peaceful or semi-peaceful means like an internal change of government, more likely by some significant level of force. With luck, perhaps some well-placed MOPs (the new deep 'bunker-buster' bombs) would cripple the program with minimal collateral: short of a sudden change of attitude on their part, that's probably the best case scenario.

Blockading the Straits of Hormuz would be extremely risky: apart from anything else, cutting off the flow of oil out of the Gulf also means cutting off the flow of money in the opposite direction, and if you think cutting off OPEC's third of the global oil supply would hurt us, think how countries like Saudi (not exactly unarmed) will feel about suddenly losing 90% of their exports and more than half their GDP? It's also a pretty blatant act of war - pretty much asking for a reenactment of Iraq's invasion of Kuwait.

I read earlier today that part of the back-story to this may be a power struggle between two factions within Iran - though with both factions being genocidal theocrats who disagree only about the means, that probably isn't much comfort to us.