Many of the comments include various scenarios of Iran being pulverized the second that the USA believe that it is Iran's intention to block the Hormuz Strait. Iran would be bombarded back to the Middle Ages by the USA, UK and French armed forces with no doubt some covert assistance from Israel.

What these writers do not take into consideration is the reaction of Russia and China. Iran has close relations with both these countries and while China and Russia have voted with the West for sanctions against Iran on the UN Security Council it is an entirely different matter to belligerent acts of war.

Iran today is practically being held to siege which in itself is an act of war and even though this siege has the blessing of the UN Security Council it is no less an act of war.

The West would be wise not to underestimate Iran, it fought a long though inconclusive war that was a result of Iraq's invasion (1980-1988). Iraq had the unwavering support both military and politically of the USA, its Western allies and US client states: Saudi Arabia, Kuwait, The Emirates, Egypt and Jordan.

Russia and China have recently watered down the sanctions that the West have placed on Syria and the Arab League plan has been effectively scuttled even though Assad has been forced to accept observers he has managed to have all sanctions, lifted. Bashar Al Assad has been given no more than a slap on the wrist. And Secretary of State Clinton has failed miserably in her aim to put a wedge between Syria and Iran.

It isn't in the interest of either China or Russia to accept that the USA have total hegemony of the Middle East and they will do what they need to do to prevent it.

It would be foolish indeed to believe that a war against Iran would be a walk in the park for the Western powers that's what they thought Iraq would be and Iraq was many times weaker than Iran is today.

Obviously a narrow strait like this would be easy to blockade.
However I would draw attention to the tanker driver strike in the UK
a few years back.
In three days the supermarkets were virtually stripped bare.

It would probably take a week or two before service stations were
affected and then another week before food ran short, then a couple of
weeks before starvation set in.
Once people realised the implications those timescales would be shortened.

Even though the gulf is the source of only about 20% of world supply
the effect would be the same as if it was very much more.
Faced with mass starvation in Europe, Nth America and most other parts
of the world there are not many choices.
How would China react to its contracted supply being cut off ?

How long after that before Iran was a sheet of glass ?

It is not a realistic path for Iran.
Perhaps they think Allah will protect them, and that is where the worry should be.

Well we may soon discover whether Iran is able to block the Straits of Hormuz.

Iran Threatens to Block Oil Shipments, as U.S. Prepares Sanctions

http://www.nytimes.com/2011/12/28/world/middleeast/iran-threatens-to-block-oil-route-if-embargo-is-imposed.html

>>WASHINGTON — A senior Iranian official on Tuesday delivered a sharp threat in response to economic sanctions being readied by the United States, saying his country would retaliate against any crackdown by blocking all oil shipments through the Strait of Hormuz, a vital artery for transporting about one-fifth of the world’s oil supply.

[...]

Apparently fearful of the expanded sanctions’ possible impact on the already-stressed economy of Iran, the world’s third-largest energy exporter, Mr. Rahimi said, “If they impose sanctions on Iran’s oil exports, then even one drop of oil cannot flow from the Strait of Hormuz,” according to Iran’s official news agency. Iran just began a 10-day naval exercise in the area.

In recent interviews, Obama administration officials have said that the United States has developed a plan to keep the strait open in the event of a crisis. ....>>>

Faced with mass starvation in many parts of the world, including
Australia, how long before drastic action was inevitable do you think ?
Can you imagine the US and Europe standing by and sucking their
thumbs while their populations went hungry ?
Will China and Japan likewise do nothing ?
Japan needs four 2 Million barrel tankers to arrive in Japan each day.

If you think my mention of Australia is far fetched think of this;
We produce about 40% of the oil we use.
We do not refine petrol in eastern Australia.
I think Kiwana refinery in WA does.
Diesel would be in very short supply.
All food is distributed using diesel.
All food is produced using diesel.
Coal is mined using diesel.
If electricity supply was interrupted many would be unemployed.

Do you still think a blockade is an option for a sane government ?

Bazz,

(1) I doubt the Iranians are crazy enough to attempt a blockade of the Straits.

(2) If perchance they try it I think the US Navy will re-open the Straits in a matter of days if not hours

(3) Russia and China may huff and puff in public but will do nothing. Quietly China will be grateful that the Americans are keeping the oil flowing.

(4) The WORST CASE scenario is a supply hiccup lasting at MOST a week.

(5) Ulis is fantasizing.

Yes Steven, I think you would have to be correct, it would only
be in effect for a couple of days.
What I have not done is look at some charts of the area.
There could be draft choke points,
There are are two designated shipping channels, one in, one out.
A couple or three large loaded tankers sunk at a choke point might be possible.
How long did it take to clear the Suez canal ?
I am sure the Iranians have thought of all that as no doubt have the
US Navy et al.