Reuters says it’s a landslide — 66/31 with 61 percent of the ballots counted — but his opponent, Mousavi, is claiming he was cheated, an excuse he’s been pushing since before the polls opened. The White House spin is set for either outcome: If Mousavi pulls the upset, it’s a hugely significant Change that proves the Iranian public wants detente, and if Ahmadinejad holds on, it’s a meaningless exercise in faux democracy given that all ultimate power derives to the Supreme Leader. Complicating all this, of course, is the fact that only the Mahdi (and the Iranian powers that be) know what the actual vote totals are. If there really was some secret groundswell for Mousavi as a protest vote against Ahmadinejad, we might see Iranian diplomacy tack — gently — towards “wider liberties at home and a gentler face for Iran abroad,” per Mousavi’s platform. But what if the numbers are accurate? Turnout was reportedly enormous, which makes lots of sense given public dissatisfaction with how Ahmadinejad’s managed the economy but zero sense in terms of producing a runaway win for the incumbent. To blow out Mousavi by 35 points with the opposition energized and headed to the polls in droves means either (a) the vote totals are cooked or (b) frighteningly, Iranians have embraced his belligerence towards the west and endorsed the regime’s rejectionism on nuclear negotiations. The poll of Iranian public opinion that I linked Monday actually suggested the opposite, that Iranians would be willing to tolerate inspections for nukes in exchange for an economic thaw with the west. So again, how to explain these results?

Regardless of who wins, I don’t mean to oversell Mousavi as some sort of radically liberal alternative to Ahmadinejad. As with all mainstream Iranian pols, the differences here are a matter of slight degree. As Iranian PM in the 80s, he condoned the killing of Salman Rushdie and there’s an argument to be made that him winning the election would actually make Iranian nukes more likely, not less. (“A Mousavi victory’s likely effect would be to make it easier for the West to trust the Iranian regime without making the regime more worthy of trust.”) To the extent the outcome’s significant, it’s significant purely as a barometer of Iranian popular opinion, not for any tidal shift in how the country will be run. Looks pretty grim right now.

Update: Given how quick some in the media were to credit Obama’s Cairo speech with the happy outcome in Lebanon’s election, will they be equally quick to call it a failure if Ahmadinejad wins? Expect them to blame it on Iran’s media censors not having let the spirit of Hopenchange penetrate deeply enough.