TENSIONS in the Strait of Hormuz are at a more than 20-year high after Iranian authorities threatened to close the 34-mile-wide channel through which more than one-third of the world's oil tanker traffic passes. The threats come against the backdrop of renewed international discussion of sanctions in the wake of an International Atomic Energy Agency report cataloguing Iranian efforts to develop nuclear weapon technology.
Many academics and retired diplomats call for renewed diplomacy and less coercion. A letter sent last month to the White House by the former British, French and Italian ambassadors to Iran declared that while sanctions have a place, winning Iranian concessions "requires the renewal of effective negotiations".
Amin Saikal, a professor at the Australian National University, suggested on this page this week that Western concerns about Iran's nuclear intentions were misplaced, and argued that, regardless, the West had no choice but to negotiate. "Neither sanctions nor military operations can really work," he declared. He is wrong.
To relieve economic and military pressure on Iran would be counterproductive. So long as Iran does not attain nuclear weapons, its threats to close the Strait of Hormuz remain simple bluster. If Iran is allowed to develop nuclear weapons, all bets are off. Tehran's ability to amplify its leverage over the international economy would increase exponentially.
Make no mistake: Iran cannot close the Strait of Hormuz for more than a day. When its navy mined the Persian Gulf in 1988, damaging a US vessel, president Ronald Reagan responded with Operation Praying Mantis, decimating the Iranian navy, a bloody nose that led Tehran to respect international waters for more than two decades.
Nor can Iran itself afford a closure of the strait. Not only does it need to export oil itself through the waterway, but, because of decades of financial mismanagement, it also depends on the strait for the import of refined petroleum products.
Without imported gasoline to fuel its car and factories, Iran's economy would grind to a halt. To close the strait even for a day would do far more economic damage to Iran than it would to Australia, east Asia or the West.
The leadership in Tehran knows better than anyone that every time Iran has experienced a fuel shortage, protesters have poured into the streets.
Despite bluster that sanctions have had no effect, Iranian behaviour suggests the opposite. Both the March 2007 Iranian attack on British sailors in the waters between Iraq and Iran, and the November 2011 attack on the British embassy in Tehran, came two days after the British government lent its support to new sanctions. Both attacks were overreactions that belied Tehran's insistence that sanctions are meaningless.
Even Iranian parliamentarians do not buy their government's rhetoric. Last month, 30 representatives called for a closed session of the parliament in order to dispense with polemic and to discuss sanctions truthfully. Abolghasem Mozaffari, the head of the Revolutionary Guards' economic wing, confessed that "the sanctions have not been without impact".
Iran's current provocations may have more to do with its own desperation than any real grievance. After the US Congress imposed unilateral sanctions on Iran last month, Iran's currency lost nearly half its value. Unemployment and inflation are both in double digits.
To keep afloat, Iran needs high oil prices. Simply threatening tanker traffic drives up the price of oil, adding hundreds of millions of dollars to Iran's coffers. The irony of such a psychological strategy, however, is that the spike in oil prices mitigates any increase that would result from military strikes.
Nor are military strikes as difficult as some believe. While Saikal argues that "most Iranian nuclear installations are buried deep underground", itself an admission that they have no civilian purpose, pilots point out that they need only destroy entrances to such facilities rather than blast the underground centrifuges, reactors and potential assembly plants and storage depots.
While no Australian, American, or European wants to pay more at the petrol pump, the status quo is unsustainable. Should the Islamic Republic develop nuclear weapons, Tehran will have a free hand to lash out indiscriminately, feeling secure behind its own nuclear deterrent. A limited conflict in the Persian Gulf might add $20 to the price of oil for a month, but a nuclear Iran could permanently add $100 a barrel.
History can be a guide. Twice, in the Islamic Republic's history, revolutionary authorities have sworn no surrender. In 1979, they said they would not release their American hostages until Washington met revolutionary leader Ayatollah Khomeini's demands. Then, they said they would accept no end to the Iran-Iraq war until Saddam Hussein was in Iranian hands. In both cases, however, isolation and sanctions took their toll.
When Khomeini announced a ceasefire with Iraq, he likened it to drinking a chalice of poison but said the cost of continuing to fight gave him no choice.
When it comes to Tehran's nuclear program and its Hormuz threats, it is time to hand Iranian leaders such a chalice, not to relieve the pressure.