The European Union yesterday reached a preliminary agreement to ban imports of Iranian oil. On Saturday, President Obama signed a bill imposing new sanctions on Iran’s central bank. The intention is to pressure Iran to curtail its nuclear program. But Tehran has responded with threats to close the Strait of Hormuz and attack U.S. naval vessels in the Gulf. The country also launched an anti-American campaign in Afghanistan. Diane and her guests discuss what is behind the recent escalation of threats and sanctions, the political and economic implications and whether military conflict is becoming more of a concern.