Monday, August 29, 2016


Explainer: Iran's Threat to Blockade The Strait Of Hormuz

An Iranian Revolutionary Guards Corps boat during training exercises in the Persian Gulf in 2007
An Iranian Revolutionary Guards Corps boat during training exercises in the Persian Gulf in 2007

A hard-line Iranian newspaper considered to speak for Iran's supreme leader has come out in support of closing the Strait of Hormuz in the Persian Gulf, the world's most important oil-shipping lane, as punishment against countries that have sanctioned Tehran over its suspect nuclear program.

A December 13 editorial in "Kayhan" asks, "Why has the Islamic Republic of Iran not used its unchallengeable right till now, when there is a conspiracy of imposing sanctions against our country's oil?" 

The piece comes a day after an Iranian lawmaker reportedly said the country's military was planning to hold drills to practice closing the vital shipping passage. The news agency ISNA quoted deputy Parviz Sorouri as saying, "If the world wants to make the region insecure, we will make the world insecure."

Julian Lindley-French, a professor at the Royal Military Academy of the Netherlands, says Iran's intent appears clear. "If this threat was carried out, in a sense -- denial of access through the Strait of Hormuz -- then [Iran] will be on a direct route of confrontation with the West and, indeed, many of the regional powers," he says.

That's because the strait -- which runs mainly along Iran, but also touches Oman and the United Arab Emirates -- is the only way for Persian Gulf oil to reach the open sea. An estimated 15.5 million barrels of oil are shipped through the strait every day -- one-third of all seaborne-traded oil, or 17 percent of the world's supply.

Any interruption in those shipments would send shock waves through the world's already-fragile economies. Already, news of Iran's unconfirmed threat has driven oil prices up $3, to more than $100 a barrel.

Theodore Karasik of the Dubai-based Institute for Near East & Gulf Military Analysis says that's nothing compared to what would happen if Iran follows through on its threat. "The consequences are that international shipping, in particular in terms of energy, would grind to a halt and this would put immense pressure on the economies all around the world," he says. "You'll see the price of oil skyrocket, probably up to $250 a barrel."

Law Of The Sea

Iran says closing the waterway is justified because governments like the United States and Britain have imposed economic sanctions on Tehran over its nuclear program, which they believe is a front for weapons development and which Tehran insists is peaceful. Iran's saber-rattling in the strait is aimed at heading off increasing efforts to curb its oil exports, and it says maritime law supports such a move.
But James Kraska, a professor of international law at the U.S. Naval War College's Center for Naval Warfare Studies, says relevant law in this case is the UN's 1982 Convention on the Law of the Sea.

"Under that convention, transit through international straits is guaranteed for all countries, so there would not be a legal basis to close the [Hormuz] Strait," he said. "And transit through the strait includes transit in the air, on the surface, as well as under the water. There's no requirement to seek the coastal states' permission, and there's no lawful basis for the coastal states to impede the transit."

Neither Iran nor the United States are among the treaty's 150 signatories, but Kraska says the convention is "customary law" that has been recognized for centuries. The waters in the strait have dual status, he says. They are technically Iranian territory, but they are also an international strait, and that gives foreign ships "a higher right of transit."

Naval Power Rules

But let's say Iran blocks it anyway. Does it have the military capacity to then take on a naval power like the United States, which is certain to respond?

A 2008 report by the Washington Institute for Near East Policy said Iran was "essentially in control of the world's oil lifeline" and had the capability to "wage unique asymmetric warfare against larger naval forces." The institute's Michael Eisenstadt says blocking the strait is "something Iran has been preparing for for years."

"Iran has been investing for decades now on creating a naval guerrilla force which would have the capability of at least interfering with shipping through the Strait of Hormuz and perhaps closing it, at least temporarily, using a combination of mines, small boats, antiship cruise missiles, submarines -- both midget submarines as well as conventional submarines -- and most recently ballistic missiles," Eisenstadt says.

Karasik of the Institute for Near East & Gulf Military Analysis agrees. "Iran's specialty is asymmetric warfare," he notes. "This is what they practice in their simulations and their exercises. This includes the use of small ships or boats, also suicide boats, underwater warfare capability, combined with the use of ballistic and cruise missiles. So they can pack a punch if they are able to get these weapons off the ground."

But like Karasik, Eisenstadt says if Iran does succeed in blocking the strait, it could only do so for about a week. "The bottom line is, although the Iranians have been talking a long time about closing the Strait of Hormuz, they probably only have the ability to do so for several days," he says. "And once the United States Navy gets involved in ensuring freedom of navigation, I think it's very clear that the outcome will be, eventually, the destruction of the Iranian Navy and the reopening of the strait."

And that may be why the threat could very well remain only that.

Written by Heather Maher, with additional reporting from Antoine Blua and Abubakar Siddique

This forum has been closed.
Comment Sorting
by: Joe
December 14, 2011 17:31
I thnk this problem is harder than this article makes it seem. The distruction of the IRIN - the regular navy, is easy - just a few large ships. The problem comes with the IRGCN - literally thousands of small boats, this is how Iran would close the SOH with. It's hard to take out one small boat - you would need to directly hit the engine or take out the people. Try doing this with 10s or 100s coming at you at the same time.
In Response

by: Andrew from: Auckland
December 14, 2011 18:31
Not really, those small boats are very fragile, and there are always cluster bombs and FAE's
In Response

by: Joe
December 16, 2011 04:25
You can put lots of holes in fiberglass hulls and it will still float.
In Response

by: Andrew from: Auckland
December 29, 2011 10:46
Small fast attack boats tend to explode violently when hit, and anyway, if you hit a boat like that with an FAE it will be crushed.

And no, you can't put a lot of holes in a fiberglass hull and still have it float if it is filled with water as a result

by: whoknows
December 14, 2011 23:23
It is almost cute how the author brings up the UN's 1982 Convention on the Law of the Sea but leaves out crucial details, the right of refusing non-innocent passage:

Article 19:

1. Passage is innocent so long as it is not prejudicial to the peace, good order or security of the coastal State. Such passage shall take place in conformity with this Convention and with other rules of international law.

2. Passage of a foreign ship shall be considered to be prejudicial to the peace, good order or security of the coastal State if in the territorial sea it engages in any of the following activities:

(a) any threat or use of force against the sovereignty, territorial integrity or political independence of the coastal State, or in any other manner in violation of the principles of international law embodied in the Charter of the United Nations;

(b) any exercise or practice with weapons of any kind;

(c) any act aimed at collecting information to the prejudice of the defence or security of the coastal State;

(d) any act of propaganda aimed at affecting the defence or security of the coastal State;

(e) the launching, landing or taking on board of any aircraft;

(f) the launching, landing or taking on board of any military device;

(g) the loading or unloading of any commodity, currency or person contrary to the customs, fiscal, immigration or sanitary laws and regulations of the coastal State;

(h) any act of wilful and serious pollution contrary to this Convention;

(i) any fishing activities;

(j) the carrying out of research or survey activities;

(k) any act aimed at interfering with any systems of communication or any other facilities or installations of the coastal State;

(l) any other activity not having a direct bearing on passage.

Let's not forget the articles on foreign warships:

Non-compliance by warships with the laws and regulations of the coastal State

If any warship does not comply with the laws and regulations of the coastal State concerning passage through the territorial sea and disregards any request for compliance therewith which is made to it, the coastal State may require it to leave the territorial sea immediately.

That sums up a large portion of the current traffic through the SOH.
In Response

by: alek from: USA
December 28, 2011 13:02
That is if the traffic lane are within its territory which are not. most of it are within Oman's territorial waters.
In Response

by: tehrna from: egypt
December 28, 2011 18:22
Most? So some are located in Iran's territorial waters? So...they can legally block those, right?
In Response

by: alek from: USA
December 29, 2011 00:02
If their threats are serious, they would probably have to go beyond their territorial waters to shut down all traffic. This alone would constitute an illegal action on the part of Iran.
In Response

by: Monte
January 07, 2012 04:58
So... of points A-L which one would an oil trade ship fall under? Seems like based on those points Iran is NOT allowed to block the movement of a civilian oil tanker which is what they want to do; so their author's point still stands.

by: Arash from: UK
December 15, 2011 03:54
An important point which has not been mentioned in this article is the extreme timidity of the Iranian tyrannical regime's leaders and its terrorist Pasdaran. Mullahs and their armed thugs are well-known for being corrupt and seeking better lives for themselves, and once faced with a stonger power, will hide run away from confrontation. Instances that can easily demonstrate the fear of power within this dictatorship are the acts of Khomeini and the terrorist leader who succeeded him. Khomeini was frightened of the Shah when in power, and even referred to him as "The Shadow of God on Earth. Similarly, when the current leader Khamenei was the Khomeini's "president", he didn't have the spine to go against Khomeini's choice of "prime minister" who was Mousavi whom Khamenei opposed.
Furthermore, as with any dictatorship, when the head hides in fear or dies, the whole regime will collaps.

by: Joe Chernicoff from: Las Vegas, NV
December 20, 2011 18:02
Robert D. Kaplan's book "Monsoon" was direct in pointing out that we need to increase the number of ships for the Indian Ocean, South China Sea, and Arabian Sea, in order to make sure that we would not have problems with our merchant ships, etc. So the Strait of Hormuz is another example of our need to build more ships, rather than once again possibly reduce our naval fleet size.

by: longshot scott from: Rome,Ga
December 25, 2011 18:53
Iran doesnt have the balls to do it , Just a bluff. They know they would lose there entire navy .Plus give America a reason to attack nuclear sites.

by: Alek from: USA
December 27, 2011 20:32
I think the author failed to mention the fact that most of the passage lanes for marine traffic are located in Oman's territorial waters.

If Iran were to make good on its threats, they would definitely would be engaging in an act of war against another state. Therefore, it would be an illegal action (under the UN charter) that would require international measures that could include force in order to restore law and order.

by: Mark Khoury from: Canada
December 29, 2011 17:27
The conclusions are erroneous on several fronts, for several reasons, and on several


Having served as a military officer, I put on my military planner's cap and evaluate

this SoH closing from a purely tactical perspective -- putting aside all politics,

good-vs-bad, who's right and who's wrong. Conclusions:

1. The threshold for closing the SoH is _much lower_ than the threshold for keeping it

effectively open.

The party wishing to close the straight does not need a 100% success rate to do so --

i.e. they don't have to stop / kill every single ship. The multiple tools at Iran's

disposal as listed in the article assure that at least one of them will get through

and affect a kill. And that's all you need.

Commercial shipping is not military shipping, and private companies will not want to

send their ships and cargo through an area with a 1-in-10, 1-in-4, 1-in-8 (or

whatever) chance of being sunk. Think of the disturbance the Somali pirates have

created, with simple AK-47s and RPGs. This is enough to keep the straights closed and

negatively impact world economies.

2. Keeping the straights 100% open -- enough that civilian shipping feels safe to

maintain its current volume -- requires, from a military perspective, disabling *all*

of Iran's military capacity. Not just its navy as the article states. With land being

so close, land-based missiles, even artillery rockets, can disrupt shipping. As can a

single aircraft staying under radar and night cover zip out, fire a salvo of missiles

and return. As can a group of soldiers go out on a zodiac either on a suicide mission

or a conventional explosive-laden mission. So...

3. Keeping the straights open 100% requires a full war with Iran - take out

communications, command&control, air force, army, navy, logistics, leadership,

supplies, capacities, everything.

4. The article is remiss in ignoring other parts of the Law of the Sea that pertain,

and some of those are covered by reader 'whoknows' elsewhere in the comments section.

5. The article also falls flat in taking the interpretation of the Law from a *US*

military lawyer, one of the conflicting parties. We all saw the legal contortions the

previous US administration went through to justify the legality of torture and

rendition (both clear violations of Internationals Law).

Taking off my military cap, the geo-political impacts would be even more far-reaching

and not in the control of anyone.

- How will a more Iran-friendly Iraq behave in this situation? And what internal rifts

/ civil war will it create if those actions open a Sunni-Shia rift.

- What about Shia majorities in Bahrain -- recently suppressed in their peaceful quest

for liberty by, effectively, Saudi Arabia and the US, react and act?

- Just nearby is now-US-hostile Pakistan (certainly the military and ISI are). They

certainly have short-range military capacities.

But I won't delve into the non-military aspects, since the article is about the

capacity to close the straights. And on that, the article is incomplete and falls


Most Popular

Editor's Picks