"We organized the strongest coalition and the strongest sanctions against Iran in history, and it is crippling their economy." - President Obama
As the candidates spar over Iran, some points worth noting: There's no question Iran's economy is ailing.
Some of that is from sanctions. Some of the problems -- a bad spike in inflation -- may be caused by internal reforms Iran has put in place to phase out fuel and food subsidies, something it is doing at the encouragement of organizations like the International Monetary Fund.
If the history of sanctions teaches anything, it is that regimes can last a long time under duress. Consider Iraq and Libya.