The motto of the American South during the Civil War was Deo Vindice - God will vindicate, will justify - God is on our side.
God was not one of Abraham Lincoln's favourite subjects, but during that war he is attributed with saying, "...my concern is not whether God is on our side; my greatest concern is to be on God's side..."
You are not justified nor vindicated by a sanction from God, but regardless of the partisanship of any particular deity, what is right and good will be most God's 'side', and that goes for most people's' idea of God.
The watching world is filled with people avowing that the demonstrators represent the spirit of freedom and true democracy in Iran. Leaders are being urged to act to support them.
Regardless of the vigour and passion on either side of the electoral dispute, the only thing that matters here is that democracy and the will of the people is accurately carried out.
No democratically elected world leader can truly support either candidate, because it doesn't matter which wins, the democracy is flawed. Not through vote rigging, but through oppression of political opposition, free press, religious diversity and other freedoms.
Even if Iran opened the doors on its electoral process and everyone was satisfied that the true winner of the recent poll had become President, and the protests ceased, I would think it a shame because the thing worthy of true protest is the social system.
Many countries are guilty of attempting to manipulate others; throughout her history, Britain has been one of the worst. To step in and support a candidate in the context of an imposed, false democracy would be to validate the false democracy.
The only request world leaders can make of those in control in Iran is that the people are well treated and that their right to protest is respected. If that is granted, when the act of protest is not a criminal offence, true protest might arise...which would be the end of an oppressive regime. The two are the same, and calling for the respect of protest is as likely to be heeded and just as ineffectual as calling for the dissolution of the oppressive regime right off the bat.
But that is all that can be done without applying force, and that would make things much, much worse.