Seymour M. Hersh in The New Yorker:
To undermine Iran, which is predominantly Shiite, the Bush Administration has decided, in effect, to reconfigure its priorities in the Middle East. In Lebanon, the Administration has coöperated with Saudi Arabia’s government, which is Sunni, in clandestine operations that are intended to weaken Hezbollah, the Shiite organization that is backed by Iran. The U.S. has also taken part in clandestine operations aimed at Iran and its ally Syria. A by-product of these activities has been the bolstering of Sunni extremist groups that espouse a militant vision of Islam and are hostile to America and sympathetic to Al Qaeda.
One contradictory aspect of the new strategy is that, in Iraq, most of the insurgent violence directed at the American military has come from Sunni forces, and not from Shiites. But, from the Administration’s perspective, the most profound—and unintended—strategic consequence of the Iraq war is the empowerment of Iran.