A bullet has been collectively dodged here. Just think of the damage a Bush administration would have done with their predictable reaction to this situation. It makes you feel a little queasy even now.
I actually suspect that President John McCain wouldn't have done what Senator John McCain is now advocating. There aren't too many people left in positions that matter who would be so ignorant of Iranian domestic politics as to advocate America lending its official weight behind the protesters.
All through their lives Iranians have been subject to anti-American propaganda. They are told that the United States is run by 'rich Jews' who want to destroy Islam and the Iranian republic. And they have a whole list of reasons to believe so. Everyone remembers the disastrous policies and interferences by the United States. Even the moderates, the relatively pro-American ones, remember Mossadeigh, the Shah, the war against Iraq and the axis of evil.
When Khāmene’i claimed that the British and the US were pulling the strings, it is like saying Obama was backed by socialists and Islamists. Except the former claim would be accepted by a far greater percentage of the Iranian population than the latter would be by Americans. They have real cause for such beliefs.
There are many Chinese who are certain that the Tienanmen Square rallies were engineered by the CIA. Historical grievances are not forgotten as easily as we would hope, and they provide an unfortunate context to the assessment that an average Chinese or Iranian will make on the cause of various events.
The current US policy towards Iran is almost pitch perfect. Can you imagine the protests even occurring if Bush was still in power? Or McCain with his 'bomb bomb bomb Iran'? The moderates in Iran would have been sidelined into nothing. Achmadi would have won his second term with ease. Hardliners of one camp foster the hardliners in the other.