There are a couple things to say about this, all of them depressing. First, those of us who have long argued for the fundamental rationality of the Iranian regime have seen our case fundamentally weakened. A rational regime might have stolen the election. But they would not have stolen it like this, where there is no doubt of the theft.
Like pretty much everyone else, I don't pretend that I understand what's happening in Iran, but it's hard not to think that the authorities were taken by surprise by both the initial vote and then the opposition's determination to make its voice heard. There may be an element of panic at work here and a somewhat frantic effort on the part of the religious authorities to buy some time. Maybe. I don't know. We're all fumbling in the dark here. Alternatively, of course, the scale of the fraud may have been designed to send the bluntest of blunt messages to the opposition.
This is a domestic uprising, albeit one that obviously has implications for Iran's relationship with the rest of the world. But, as best I can tell, there's no suggestion that, right now at least, there's not much that's happening in Iran that has much bearing on the country's foreign policy, let alone its nuclear ambitions.
This may change, but the strategic implications of Iran's nuclear ambitions haven't changed this weekend and I don't know if there's any reason to suppose that, in the arena of foreign policy at least, the regime is any more irrational than it was this time last week.
Then again, who can tell? In the absence of any real insight into what the clerical authorities are thinking at the moment it is hard to be certain of anything. As I say, this, like everything else, may change. Even so, the nuclear issue won't go away, regardless of what happens in the coming days. But that doesn't mean it's forever frozen in amber either.
Bottom line: this brutal and ghastly regime may behave irrationally at home but that doesn't require it to behave irrationally abroad. At least, I hope not...
UPDATE: I forgot to mention that I do not believe that this has not changed the strategic and tactical imperatives for engaging Iran vis a vis its nuclear ambitions. It has. But that's a post for another day. Some aspects of US-Iran relations have been made clearer; other have been made murkier. More on this, too, later.