How do we know the Iranian elections were rigged?

Highly Improbable Numbers

The numbers. Official figures claim Ahmadinejad won 63% of the vote or 24.5M ballots cast. An extra 7M people are supposed to have voted for him since the second round of the last election when there was only one other candidate, Rafsanjani, another conservative.

What has changed since the last election:

• In 2005, following two-terms of popular reformist president Khatami, Iranians had to choose a new president, but reformists fielded several candidates. Through a combination of disatisfaction over reformist achievements during Khatami's rule,  candidates disqualified from standing, and a split in the reformist candidates that were eventually allowed to run, many voters stayed away from the ballot
• In 2005, Ahmadinejad was running in the second round against Rafsanjani, a regime stalwart, who twice served as president of Iran (during the Iran-Iraq war). The choice between the two conservatives (albeit to varying degrees) led to a relatively low turnout, and many choosing Ahmadinejad as the unknown non-cleric, non-Rafsanjani candidate
• In 2009, voters were motivated (massive turnout) and reformists solidly backed one candidate, Mousavi

There is strong evidence linking turnout with reformist victories:

• In 1997, Khatami took 70% of the vote with a 88% turnout in a reformist vs conservative election
• In 2001, Khatami was re-elected with 78% of the vote with a similarly high turnout
• In 2005, in initial turnout of 63% (already relatively quite low) dropped to 48% when the second round run-off made it a conservative vs conservative election, resulting in Ahmadinejad's election
• In 2009, a huge turnout with voting extended by four hours results in a 63% win for the conservatives?

Conclusive?

While none of this is conclusive proof that the results of the elections were rigged at the final stage, we know the dice were loaded from the outset.

Personally, I like the analogy of democracy as pregnancy; you can't be half-pregnant and you can't be semi-democratic.

The screening of candidates by the guardian council and the absence of free domestic media means that there is no democracy in Iran and that is what people are in the streets protesting about.

When they shout 'death to the dictator', it's not directed against Ahmadinejad, it's against the ‘supreme leader‘ himself.

Let's hope the protesters are victorious.