Iran Could Close Hormuz—but Not for Long

Should Iran's rulers ever make good their threats to block the Straits of Hormuz, they could almost certainly achieve their aim within a matter of hours. But they could also find themselves sparking a punishing — if perhaps short-lived — regional conflict from which they could emerge the primary losers.

AFP | Getty Images Iranian navy conducts the "Velayat-90" naval wargames in the Strait of Hormuz in southern Iran on January 1, 2012. Iran defiantly announced that it had tested a new missile and made an advance in its nuclear program after the United States unleashed extra sanctions that sent its currency to a record low.

In recent weeks, a growing number of senior Iranian military and civilian officials have warned that Tehran could use force to close the 25 mile (54 km) entrance to the Gulf if Western states impose sanctions that paralyze their oil exports.

In 10 days of highly publicized military exercises, state television showed truck-mounted missiles blasting towards international waters, fast gunboats practising attacks and helicopters deploying divers and naval commandos.

Few believe Tehran could keep the straits closed for long — perhaps no more than a handful of days — but that alone would still temporarily block shipment of a fifth of all traded global oil, sending prices rocketing and severely denting hopes of global economic recovery.

But such action would swiftly trigger retaliation from the United States and others that could leave the Islamic republic militarily and economically crippled.

"They can cause a great deal of mischief...but it depends how much pain they are willing to accept," says Nikolas Gvosdev, professor of national security studies at the U.S. Naval War College in Rhode Island.

He said he believed Tehran would only take such action as a last resort: "They are much more likely to threaten than to act."

The true purpose of its recent sabre-rattling, many analysts suspect, may be more a mixture of deterring foreign powers from new sanctions and distracting voters from rising domestic woes ahead of legislative elections in March.

With the United States signing new sanctions into law on New Year's Eve — although they will not enter force until the middle of the year — and the European Union considering similar steps, few expect the pressure on Tehran to let up.

"This is probably less a genuine military threat than a bid to put economic pressure back on the West and split Western powers over sanctions that threaten Iran's oil economy," says Henry Wilkinson, head of intelligence and analysis at London security consultants Janusian. Iran now does not have much to lose by making such a threat and a lot to gain."

But many fear the more Iran is pushed into a corner, the greater the risk of miscalculation.

Its ruling establishment is also widely seen as deeply divided, with some elements — particularly the well-equipped and hardline Revolutionary Guard — much keener on confrontation than others.

Sea Mines, Missiles, Submarines, Speedboats

"I cannot see strategic sense in closing the straits, but then I do not understand the Iranian version of the 'rational actor'," said one senior Western naval officer on condition of anonymity.

"(But) one can be pretty certain that they will misjudge the Western reaction...They clearly find us as hard to read as we find them." The capability to wreak at least temporary chaos, however, is unquestionably there.

The U.S. Fifth Fleet always keeps one or two aircraft carrier battle groups either in the Gulf or within striking distance in the Indian Ocean.

Keenly aware of conventional U.S. military dominance in the region, Iran has adopted what strategists describe as an "asymmetric" approach.

Missiles mounted on civilian trucks can be concealed around the coastline, tiny civilian dhows and fishing vessels can be used to lay mines, and midget submarines can be hidden in the shallows to launch more sophisticated "smart mines" and homing torpedoes.