Christopher de Bellaigue argues that the sanctions against Iran, like those before them against Iraq, aren't working:
[T]he U.S. is at pains to show that the Islamic Republic will gain a life-saving reprieve if it falls in with U.N. resolutions calling on it to stop enriching uranium. If that happens, Hillary Clinton said in October, sanctions might be "remedied in short order." But Iran’s supreme leader dismissed her words as a "lie." Khamenei and those around him believe that sanctions policy is part of a bigger American project of Iraq-style regime change.
There is some logic to this; recent western tactics against Iran include sabotage, assassination and diplomatic isolation—hardly indicative of a desire for detente. The most recent round of nuclear negotiations foundered, in part, on Iran’s growing conviction that the U.S. will make no significant concession on sanctions unless Iran drastically scales down its program of uranium enrichment. That seems unlikely to happen–not simply for reasons of image and prestige, but because, as American hostility sharpens, Iran may judge its nuclear program to be the best defense it has against the fate that befell Saddam.
There has to be a way to give the regime some face-saving if it retreats. Or the logic of war could drag us all along with it – a war we do not need and cannot afford.