Iran sanctions cripple ageing military
Notionally, Iran has about the biggest armed forces in the Middle East, with more than half-a-million people in uniform, but decades of US-led arms embargoes have had a huge impact on the strength of its conventional armed forces.
It has adapted, in part by changing the focus of its forces, but that has not completely made up the difference.
As well as formal embargoes and sanctions, there have been informal limits that countries have imposed on what they will and will not supply to Iran.
End Quote Anthony Cordesman CSIS Washington
More and more, Iran is dependent on systems delivered at the time of the Shah”
Since the Islamic Revolution, the country's neighbours among the Gulf Arab states have poured billions of dollars into almost unrestricted purchases of the most advanced Western weaponry.
Not so Iran.Low-tech solutions
Since the 1980s, the country has in effect been unable to modernise its armed forces properly.
"More and more, Iran is dependent on systems delivered at the time of the Shah," according to Anthony Cordesman of the Centre for Strategic and International Studies (CSIS) in Washington.
"Systems which are old in technology, where there are many countermeasures, which are wearing out or were worn out during the Iran-Iraq war, and where - with every passing year - it falls steadily behind."
In part, Tehran has compensated for this by turning to more low-tech military solutions, what is known as asymmetric or irregular warfare, often involving the Iranian Revolutionary Guards.
These include more modest naval forces, for example, that might not be able to engage in a direct naval battle, but could harass shipping in the Gulf.
And there are other ways it may be extending its influence.
"Some of the things they will do to further their political ends use relatively low-tech military equipment", says Malcolm Chalmers of the Royal United Services Institute in London.
"If you're talking about supplying Hezbollah or Hamas or the Taliban, then you're not talking about supplying them with fighter aircraft, you're talking about relatively crude surface-to-surface missiles or indeed surface-to-air missiles."Parts smuggling
Again nominally, Iran has about 300 combat aircraft.
But that does not paint the true picture.
End Quote Malcolm Chalmers Royal Services Institute, London
One of the long-term effects of arms embargoes is for countries always to become more self-sufficient”
To keep its increasingly antique conventional weapons going, Iran has resorted to smuggling in spare parts.
"This has been critical, because only about 40% to 60% of the inventory Iran has can fly, for example, out of its combat aircraft, and much less of its helicopter fleet", says Anthony Cordesman.
"But if it couldn't smuggle in spare parts, most of that fleet wouldn't be operational at all."
Of course, the history of arms embargoes is often that their impact diminishes over time.
"One of the long-term effects of arms embargoes is for countries always to become more self-sufficient, to develop their own manufacturing capability," Malcolm Chalmers says.
"And we saw that historically in South Africa, which developed - under apartheid - a very competent military-industrial capability which it would not have developed if there had not been an embargo."Missile advances
Iran has certainly invested heavily in building its own ever-longer-range missiles, in part again to compensate for its weak air force.
It is perhaps the most significant military capability - apart from the suspected nuclear one - that the West and its regional friends worry about.
This missile development has been with the help of others, like North Korea.
But, in some respects, Iran may now be the most active developer of such systems, surpassing Pyongyang.
In other areas, it has not been very successful in developing its own weaponry. "There've been very few of these weapons actually produced," says Anthony Cordesman.
"Most of them have not gone into inventory. In other cases they simply have lied about the capability of weapons systems that can't perform at anything like the level that you sometimes see reported in the press."Regional threat
Some countries, like Russia and China, have been willing over the years to supply Iran with less advanced weapons.
But even that has been hostage to the diplomatic climate.
There may be limits to the consensus on the new sanctions. But they clearly tighten the rules on military supplies.
And, with the new squeeze, there seems little chance that Russia - for example - will sell the much-talked-about advanced S-300 air defence missile.
"As of today, Russia does not have a legal obligation not to sell S-300 to Iran," says Vladimir Orlov of the PIR Centre in Moscow.
"At the same time, Russia does not have the intention to sell the S-300 to Iran currently, when Iranian behaviour is actually quite hostile towards Moscow."
All this has clearly been a conventional military handicap to Tehran.
But, while it may not be able to project conventional military power, it seems to be able to project unconventional military influence.
And, with its asymmetric capabilities, it can pose regional problems for its neighbours and their allies, and perhaps threaten their economies.