"The Obama Administration identifies Iran as a major threat to U.S. national security interests. This perception is generated by suspicions of Iran's intentions for its nuclear program-- heightened by a November 8, 2011, International Atomic Energy Agency (IAEA) report--as well as by Iran's support for militant groups in the Middle East and in Iraq and Afghanistan. U.S. officials also accuse Iran of helping Syria's leadership try to defeat a growing popular opposition movement and of taking advantage of Shiite majority unrest against the Sunni-led, pro-U.S. government of Bahrain. Tensions have been particularly elevated since Iran's late-December 2011 threat to try to choke off much of the world's oil supplies by attempting to close the Strait of Hormuz--a reaction to the imposition of significant sanctions against Iran's vital exports of oil. The sense of imminent crisis with Iran--much of which has been brought on by Israeli threats to buck U.S. advice by acting militarily against Iran's nuclear program--follows three years in which the Obama Administration has assembled a broad international coalition to pressure Iran through economic sanctions while also offering sustained engagement with Iran. None of the pressure has, to date, altered Iran's pursuit of its nuclear program: Iran attended December 2010 and January 2011 talks with the six powers negotiating with Iran, but no progress was reported at any of these meetings. However, since the beginning of 2012, as significant multilateral sanctions have been added on Iran's oil exports--including an oil purchase embargo by the European Union to go into full effect by July 1, 2012--there are growing indications that the regime feels economic pressure. Iran's leaders have responded not only with threats to commerce in the Strait of Hormuz, but also stated a willingness to enter into new nuclear talks without preconditions. At the same time, it has begun uranium enrichment at a deep underground facility near Qom. The Administration uses indicators such as Iran's economic deterioration and its willingness to engage in new talks as evidence that policy is starting to work and should be given more time before any consideration of U.S. or other country military options."
CRS Report for Congress, RL32048