Sanctions have not often worked to get governments to change their behavior, but Iran may prove to be an exception. The country depends on income from oil sales, and the oil sector is highly vulnerable to sanctions.
The United States has stopped buying Iranian oil, and the European Union is set to do so at the end of next month. There are sanctions on Iran's central bank and punishments for companies that help Iran ship its oil.
Jamie Webster, an oil market analyst at PFC Energy, says Iran's oil exports — normally about 2.5 million barrels a day — are in serious jeopardy.