Andrew may wince, but the President’s statement on the lack of significant policy differences between Ahmadinejad and Mousavi is just simply true. More precisely, it is true with respect to all of the foreign policy and national security questions that are at the top of any list of outstanding differences between Washington and Tehran. If Mousavi differs from Ahmadinejad in these areas at all, it is as a matter of presentation, tone and style, not on the substance of the policy.

Mousavi’s spokesman complained that Obama probably doesn’t like being identified with Bush, but there are times when recognizing continuity between the two is appropriate and realistic. There are times when they really do have the same policies. There are other issues where the differences between them couldn’t be more clear, as Bush made a point of reminding us this week. These differences may not be very great in the grand scheme of things, inasmuch as Obama and Bush broadly agree about American “leadership,” power projection and an expansive definition of national interest, but they exist. Compared to the differences between Obama and Bush on foreign policy, which are few but real enough, Ahmadinejad and Mousavi are even closer together. Before the election, someone called Mousavi Iran’s Kerry, which was a bit of an insult to Kerry, because by 2004 even Kerry was farther away from Bush on foreign policy than Mousavi is from Ahmadinejad today.

This is to be expected. In any political system, the candidates that are deemed acceptable and within the national “mainstream” will not differ from each other very much. In the Iranian system, where all candidates are vetted ahead of time to ensure that the differences are even smaller and their acceptance of established security and foreign policies is even more certain, this is even more the case. Besides, as Obama’s supporters never tired of stating in his defense during the campaign, it is the Supreme Leader and not the Iranian President who sets policy and has the real control anyway, which tends to drive home just how unimportant the differences between the two men are in this case. As much as people might say things like, “Ma mitavanim” (we can) there are things that Iranians really cannot do that American voters still can. They cannot vote for someone who would introduce fundamental policy changes in these areas, because no one who would make those changes is permitted to participate. We all know there are constraints that force our presidential nominees to hew towards certain conventional “centrist” policies that the political class endorses and defends, and in Iran the constraints are even stronger and the means for loosening them even fewer.

However much people may want to liken Mousavi to Obama, they are really nothing alike, and you have to marvel at Obama supporters who would want to draw such a comparison. Obama has plenty of faults, but he has not executed domestic political opponents by the thousands. Obama may be an establishmentarian by instinct, which is how he got to where he is, but Mousavi has always been a part of the establishment in Iran. If we focus on the individual leaders to find some indication of changes in policy, we are fooling ourselves. In the best-case scenario, Mousavi is a rallying point around and a vehicle through which an entirely different kind of political force can organize.

Provided that we don’t exaggerate this point, I should say that personal differences in political leaders can be important. One need only compare the ridiculous John McCain and his response to the events in Tehran with Obama’s measured and responsible actions to be reminded that personality and character can make a difference in the conduct of the affairs of state, but more important than the difference between Obama’s reserve and McCain’s hot-headed recklessness are their different attitudes towards Iran. Obama may remain firmly aligned with the American establishment in rejecting Iranian nukes and keeping the military option “on the table,” but he does not disdain negotiations with Tehran as McCain does. As small as that difference is, it makes a difference. Could there be similarly small, but significant differences between Mousavi and Ahmadinejad? Of course. But no one should oversell this or place too much hope in Iranian policy changing dramatically as a result, just as no one should expect Medvedev to differ greatly from Putin on those issues that the Kremlin believes are central to Russian interests and national security.