Mahmoud Ahmadinejad has now made the mistake that all Iranian presidents make: He has challenged the authority of the country's Supreme Leader, Ayatollah Ali Khamenei. He is doomed to fail.
The challenge posed by Ahmadinejad is such a predictable part of Iranian politics that it has come to be known as "the president's symptom." It emerges from a president's confidence that, as a popularly elected leader, he should not be constrained by the Supreme Leader's oversight. But the Islamic Republic's history is littered with its presidents' failed attempts to consolidate an independent power center.
Ultimately, divine authority trumps political authority.