Throughout history, tyrants have exploited the vulnerability of their subjects. This vulnerability is inevitably linked to a lack of economic clout.
So now, the US is considering sanctions against Iran. What do sanctions do? They limit economic growth. What happens when a people are economically impoverished? They lack the power to change their circumstances. If you want to make a tyrant more secure, just take away the power of his people.
Do sanctions work? Castro's decades of rule in Cuba might suggest that they don't. It's not at all clear that there are examples that suggest that they do. Oh well, I guess as futile gestures sanctions are better than war.