What would sanctions on Iran accomplish?

Rebecca Griffin, political director of Peace Action West, writes in the San Jose Mercury News that there is little evidence to support the idea of imposing sanctions on Iran. "In the past 30 years, there has not been a single instance of U.S. sanctions eliciting positive changes in the Iranian regime's behavior...The belief that sanctions lead people to rise against their government is also wishful thinking.In fact, Iran's nuclear technology program enjoys widespread public support. Hostility from the United States would give Ahmadinejad means to rally his crumbling base by bolstering a favorite narrative: The U.S. government threatens Iranians and does not respect their sovereignty and regional power."  Griffin, who traveled to Iran in May before the tumultuous elections, argues that "President Barack Obama laid the groundwork for rethinking our relationship with Iran. Congress should step back and allow the administration's good faith diplomacy to bear fruit."<