This account by Iranian film director and Mousavi spokesman Mohsen Makhbalbaf makes a great deal of sense:
"According to Mr. Makhbalbaf, in the early hours after voting had ended, the Interior Ministry had called Mr. Mousavi’s campaign headquarters to inform them that Mr. Mousavi would be the winner and, therefore, Mr. Mousavi must prepare a victory statement. Mr. Mousavi was, however, asked by the Ministry not to boast too much, in order not to upset Mr. Ahmadinejad’s supporters. Many of the president’s supporters are among the ranks of the Basij militia, and thus armed.
"According to Mr. Makhbalbaf, the Supreme Leader, Ayatollah Ali Khamenei, was also informed of the developments. He also recommended a 'good management' of the victory statement, meaning not boasting greatly about the victory, because that would be in Iran’s national interests and stability.
"At the same time, the reformist newspapers were also informed that they can prepare their Saturday edition to declare Mr. Mousavi the winner, but were not allowed to use the word pirouzi (victory) in their articles, in order not to upset Mr. Ahmadinejad’s supporters. One reformist newspaper prepared its front page with the title, 'People took back the flag of their country [from Mr. Ahmadinejad].'
"But, just a few hours later, a center that had been set up by Mr. Mousavi in Gheytarieh (in northern Tehran) for monitoring the election and vote counting, was attacked by armed security agents. They ransacked the center, destroyed computers, and attacked the staff. Supporters of Mr. Mousavi intervened and arrested 8 security agents. The police was called to take them to prison, but the police released the attackers.
"According to Mr. Makhbalbaf, the central headquaters of Mr. Mousavi’s campaign was also surrounded by security forces, as was the Interior Ministry building. Then, new data began to be released by the Ministry, indicating that Mr. Ahmadinejad had won the elections decisively."
A coup that originated with the military rather than the clerical or lay political leaders resolves what I saw the the main flaw with Juan Cole's reconstruction.
It also dovetails well with Interior Ministry employees' warnings that Ayatollah Mesbah-Yazdi, who is influential in the military, issued a fatwa authorizing manipulation of the elections.
A coup led by the military is also easier to explain than one ordered by Ayatollah Khamene'i. I had been thinking about the implications of a Mousavi victory, and concluded that, given the continuing conservative dominance of Parliament, the most important changes for Iranians would be a different economic policy and the replacement of someone hostile to the old revolutionary establishment embodied by the likes of Rafsanjani with someone who was actually a part of it. With that in mind, let's go to Walter Posch's election backgrounder:
"On the other hand, if Ahmadinjed wins, the relatively broad scope of political participation for various ideological and political trends will be dramatically reduced, as the reformists will be pushed aside and purged. This in turn will lead to an ideological monopoly for Mesbah-Yazdi and the Haqqaniye network, where a new generation of political clerics is trained. This also means a final legitimization of the Revolutionary Guards’ control over the economy, complementing the tax-free cash cows of the 'pious' foundations and further suffocating free enterprise. Finally, it would mean the strengthened
indirect and direct control of the Revolutionary Guards over the executive branch. Former IRGC members already control most of the Parliament, are present in the government, and, of course, in the Higher National Security Council (HNSC)."
In other words, the often anti-democratic and militarily inclined forces which have been rising in Iran were threatened by the more traditional establishment, and acted to preserve their interests. We already saw, starting in 2005, how this movement had pushed together reformists and centrist pragmatists, resulting in Mousavi's alliance with the likes of Rafsanjani and Khatami's conservative 1997 opponent Ali Akbar Nateq-Nouri. If so, this was not a coup perpetrated by the clerical establishment, but by a rising hard-line counter-establishment that did not want a repeat of the 2006 elections for the Assembly of Experts.