Iran’s currency is nose-diving. There can be no disputing this fact. On Tuesday, the rial hit a record low of 36,100 for one US dollar (at unofficial street-trading rates). A week earlier a dollar cost 24,000 rials. In 2011, the figure was 10,000.This has not only imposed extreme hardship on Iran’s already hard-pressed population but also created opportunities for all players to hype their self-serving spins.Iran’s President Mahmoud Ahmadinejad as expected sought to bolster sagging morale by asserting that his country’s financial woes were all “due to psychological pressures.”In his view, sanctions constitute a component of the “heavy battle” that has been driving down oil sales “a bit.” That conceded, however, Ahmadinejad insists that his government possesses sufficient cash to make do, enabling it to ride out sanctions and to expand oil exports to Asian markets such as China.From the other side of the diplomatic divide come crows of self-congratulation. The West – both in Europe and the US – waxes triumphant. The sad state of the rial is cited as proof positive that sanctions against Iran work, that they are doing precisely what was predicted they would and that, if given more time, they will obviate the need for any other – presumably military – measures to keep Tehran from producing nuclear weapons. But is this upbeat Western spin any more credible than Ahmadinejad's pep talk to his compatriots? Odds are it is not.Even tougher sanctions would probably be less than crippling because, like it or not, Iran is not bereft of friends. Russia, China and assorted Latin American and Third World sidekicks can dent trade and banking embargoes.Moreover, even when sanctions work, it can take a long time for their effects to become so devastating as to inundate the streets with rebellious downtrodden multitudes.The tipping point of desperation may be different for long-oppressed Iranians – many of whom are poor, unemployed and subsist on very little – than it is for their softer counterparts in the pampered West. Pain thresholds are considerably higher in autocracies where the people have gradually grown inured to harsher and harsher conditions.Perhaps no society epitomizes this better than North Korea. It has been subjected to sanctions longer than any other country and its population teeters on the brink of starvation. Yet the citizenry’s welfare is hardly the highest priority for Pyongyang’s powers-that-be. They had already detonated two nuclear devices while sanctions were enforced.Tehran’s ayatollahs are hardly more caring than Pyongyang’s tyrants. Neither regime is likely to back down out of compassion for the suffering masses. And Tehran learns well from its tutors in Pyongyang.The primary lesson is that the West’s actual goal is not to prevent the world’s prime sponsors of terrorism from developing nuclear warheads as much as it is to induce them to return to the negotiating table.This wrongheaded premise failed miserably in the case of North Korea, which had no qualms to renege on its obligations almost as soon as seeming compromise was reached. Iran is equally adept at making mockery of Western envoys. Nonetheless, a similar premise decrees that suave diplomats can cool the Iranians’ ardor to harness nukes in the service of fanatical Islam.This is not to say that sanctions should be abandoned. If anything, they should be tightened. Yet at the same time we must not rely on them to deliver the ultimate goods.The only way sanctions can succeed is if they trigger critical disturbances that can topple the mullahs from power. However, the Obama administration’s cold shoulder to brave Iranian protesters in 2009 generates powerful disincentives for another attempt at regime change. Besides, successful Arab Spring uprisings were those backed by Islamists. Here we have the reverse situation of opposition to an Islamist theocracy.There is certainly dissent in Iran, but it may be concentrated among the intelligentsia rather than in broader strata of society. Privation may prove a double-edged sword and unify the masses against the West rather than the other way around. That is the principal thrust of Ahmadinejad's spin and he has time to solidify support while his nuclear centrifuges keep spinning.