This is my humble opinion on Mousavi's latest statement, which is available in Persian and English on his Facebook site.
It seems to me that this message is written with a "frame" that gives us insight into how to interpret the main body of the statement. The first and final paragraphs of the message seem more pointed than the rest, and I think it is there that we find a key to understanding the whole statement.
Mousavi writes both these framing paragraphs largely in passive voice, allowing him to indicate that certain actions have taken place in certain ways that may not have been wise, without actually laying blame at anyone's feet. Because of this we have to use inference to determine who the people are that would be involved in these actions.
The first sentence of the message after the opening invocation is, "It was constantly told to me and [my] friends that if we don’t issue any statements, people would not take to the streets and would quit their protests and demands, and peace would return to the country." This sentence is very interesting because of who is absent in it. Mousavi, his friends, and the people are the only figures directly placed in the sentence, yet the action lets us know there must be some people doing the telling. In fact there must be a lot of them because this telling is going on "constantly." Mousavi avoids describing who has been chastising him, but it's also unclear who he is now complaining about it to.
Mousavi is addressing the general reader, of course, but the point of describing other people in passive construction in an open letter is to subtly get a message across to one or more people who would be "in the know" enough to understand exactly who you mean without the need to name names. Hardline mullahs and secular leaders from many areas of Iranian society have no doubt been pressuring Mousavi to stop calling demonstrations since June, but who could Mousavi turn to about that? The people are already aware that they plan to go out on the streets regardless of Mousavi's silence, so who is Mousavi trying to convince that his words are not the source of the demonstrations?
The idea that Mousavi has one particular reader in mind is reinforced when he goes on to state how he disagreed with the people pressuring him into silence. Mousavi barely touches on this, as if to merely remind his reader of long-familiar past debates that were already hashed out at great length. This indicates the intended reader is someone privy to closed-door discussions at the top levels of Iranian politics, who doesn't need a recap of all that.
The body of the message appeals to this particular reader as if to a judge, laying out a case that, just as Mousavi had predicted, his ceasing to call people to demonstrations did not prevent massive crowds from coming onto the streets on Ashura. Mousavi gives thorough evidence that he followed the laws of Islam, did all that was asked of him, silenced his call for protest, and still the crowds came out. He was right, and those who had been pressuring him were wrong, and he wants someone in particular to know that.
Mousavi then goes on to poetically and specifically describe the current state of Iran and explain the alternative steps he thinks are the right ones to begin achieving the goal of restoring peace to the country, since silencing him didn't work. That part has been thoroughly discussed elsewhere, so I will just highlight that Mousavi refers to the current national situation as like a flooded river full of silt, and his five proposed actions as like fresh rivulets flowing into the stream to clear it.
Then in a short paragraph following his five points, Mousavi once again seems to pointedly address a particular reader. With neat symmetry, the very last sentence of the entire message is, "And the last word is that all these suggestions can be executed with wisdom, insight and good will and without the need for treaties, negotiations, and political deal makings." This is another very interesting sentence. Though once again using passive voice without naming names, things have deteriorated from a situation of general verbal chastisement to "treaties, negotiations, and political deal makings."
"Treaties" in particular is a telling word, as it implies a cessation of hostilities. With the assassination of Mousavi's nephew on Ashura, it's not really a stretch to think this might not be just a poetic turn of phrase, but more of a mafia kind of deal. One that might be negotiated as, "Put out a statement withdrawing your claim to have won the election, so the people stop protesting, and we won't kill your wife or daughter next." Whether or not that was ever explicitly said to Mousavi by anyone, some might see the assassination of the closest person to a son Mousavi has, his sister's son, as a nonverbal message to that effect.
It is worth noting that this new statement does not include any reference to Mousavi's earlier demands for an investigation into election fraud, and conservative politician Mohsen Rezaei apparently interprets the statement as a withdrawal of the election fraud claim. Although Mousavi declares he is ready to die himself as a martyr for the cause, what man would put his family at risk of further mafia-style hits?
Seemingly disgusted with whoever these would-be negotiators and treaty-makers are, whatever their demands might be, Mousavi dismisses that kind of thuggish back-room deal-making, and appeals to a higher authority. He calls out to someone who has "wisdom, insight, and good will" to hear his evidence, understand that there is nothing he can do to stop the Green Movement, and call for an end to violence and the beginning of real changes that could truly restore peace to the land. The world waits to see if the message gets through to the right person, and if that person has a change of heart in time to prevent further tragedy.