But the Supreme Leader might well call Ahmadinejad's bluff; experience has shown that the president typically caves when faced with Khamenei's immense institutional power. Even if he doesn't, Khamenei loyalists have laid the groundwork to soften the blow, announcing in advance that anyone who interferes with the electoral process or questions its results is doing the bidding of Iran's enemies. "Everyone, even those who make general recommendations about the election through [expressing] concerns, should take care not to serve the purpose of the enemy," Khamenei warned in January 2013. In other words, Khamenei can call for a witch-hunt if his patience wears thin.
Some observers argue that allowing Mashaei to run could be beneficial for the Supreme Leader. They note this would split the anti-establishment vote between Mashaei and Rafsanjani, leaving them both in a weaker position. That, however, would have been risky business, given that predicting voter behavior in Iran is an inexact science. In 1997, an underdog reformist candidate, Mohammad Khatami, rallied more support than expected in just a few weeks and went on to win the presidency. In 2009, an uncharismatic former prime minister, Mir Hossein Mousavi, morphed into an Iranian Che Guevara and inspired millions of people to protest the election results.
Allowing Rafsanjani and Mashaei to run would also have invited a serious challenge to Khamenei's conservative clique. Reformists and pragmatists would have likely united behind Rafsanjani, while Ahmadinejad's allies would have thrown their support behind Mashaei. Khamenei's camp, meanwhile, could have been the one neutralizing itself by failing -- as is so far the case -- to coalesce around one or two viable candidates.
It appears that instead of going back to the drawing board, Khamenei has concluded that a stitch in time is better than nine. He has decided to eliminate Rafsanjani and Mashaei now, rather than deal with the unpredictable ramifications of allowing them to run. But the decision is not cost free, as he has now openly demonstrated that for the man at the helm of power in Iran, security trumps legitimacy.
In contrast, both Rafsanjani and Mashaei have much less to lose. No other high-ranking Iranian official has put himself to the popular test more often than Rafsanjani. He has tasted both victory and defeat. While he won the 1989 and 1993 presidential elections, his bid for parliament in 2000 and the presidency in 2005 ended in humiliating defeat. He had a quasi-comeback in 2007 when he was elected chairman of the Assembly of Experts -- a body in charge of selecting the Supreme Leader. This time, his disqualification is likely to redeem him as a founding father of the Islamic Republic, who was denied a last hurrah by an increasingly authoritarian leader.
Mashaei's candidacy, meanwhile, was also a no-lose scenario. In the unlikely event that he would have run and won, the Putin-Medvedev model would have been successfully implemented. But now that he has been barred from running, Ahmadinejad and his team could demand a price for their silence from Khamenei. If he refuses, the gloves could come off.
Reactions to disqualifications and back room negotiations during the next few weeks will determine not the fate of the barred candidates and the constituencies they represent, but in a larger sense the fate of the republican identity of the Islamic Republic of Iran.
To say that Iranian politics is the realm of contingencies is a considerable understatement. Even now that the list of the vetted and approved candidates is out, the race could still change substantially as they maneuver and drop out. There's still more than a few hands of cards to be played before election day.
Ed. —This article has been updated to take account of the Guardian Council's May 21 rejection of the candidacies of Akbar Hashemi Rafsanjani and Esfandiar Rahim Mashaei.