"The Bush Administration has pursued several avenues to attempt to contain or end the potential threat posed by Iran, including pursuing limited engagement directly or through allies. Over the past two years, the Administration has focused primarily on blunting Iran's nuclear program by backing diplomatic efforts by European nations and Russia to negotiate permanent curbs on it. International concerns on nuclear issues and other strategic issues have been heightened by the accession of Mahmoud Ahmadinejad, a hardliner, as president. With Iran continuing to advance its nuclear program, some advocate military action against Iran's nuclear infrastructure, but others believe that continued diplomacy, combined with offers of economic rewards or threats of international sanctions, is the only viable option. U.S. sanctions currently in effect ban or strictly limit U.S. trade, aid, and investment in Iran and penalize foreign firms that invest in Iran's energy sector, but unilateral U.S. sanctions have not ended Iran's WMD programs or shaken the regimes grip on power. Still others believe that only an outright replacement of Iran's regime would diminish the threat posed by Iran to U.S. interests, and this view has apparently gained favor within the Administration as Iran has resisted permanent curbs on its nuclear program."
CRS Report for Congress, RL32048
Federation of American Scientists: http://www.fas.org/main/home.jsp