"According to the Administration's 'National Security Strategy' document released on March 16, 2006, the United States 'may face no greater challenge from a single country than Iran.' That perception, generated first and foremost by Iran's developing nuclear program, has been intensified by Iran's assistance to Shiite armed groups in Iraq and to Lebanese Hezbollah. The Bush Administration is pursuing several avenues to attempt to contain the potential threat posed by Iran, but the Administration's focus on preventing an Iranian nuclear weapons breakthrough - as well as on stabilizing Iraq - has brought multilateral diplomatic strategy to the forefront. Iran did not comply with an August 31, 2006, deadline to cease uranium enrichment, contained in U.N. Security Council Resolution 1696 (July 31, 2006). After almost four months of negotiations during which Russia and, to a lesser extent, China, argued that diplomacy with Iran would yield greater results than would sanctions, the Security Council imposed modest sanctions on trade with Iran's nuclear infrastructure and a freeze on trade with and the assets of related entities and personalities. (Resolution 1737, passed unanimously on December 23, 2006). Iran remained out of compliance, and the international community increased sanctions in a follow-on, Resolution 1747, adopted unanimously on March 24, 2007."
CRS Report for Congress, RL32048