[Editor's note: Today, GlobalPost begins rolling out extensive coverage — in words and pictures — of the 2009 Iranian presidential election. Read more about the "Michelle Obama" of Iran, and why this election is different from any other in the Islamic Republic's 30-year history.]

TEHRAN, Iran — Iranians imagined that this year’s presidential campaign would be hard fought, but no one quite expected what it has become: a spark for uncontrolled street revelry; a platform for hostile name-calling between ill-tempered candidates; and an opportunity to hold a referendum on the achievements of the 1979 revolution.

The mantle of "change" has been bestowed on an unlikely candidate: Mir-Hossein Mousavi is a graying throwback to the early days of the revolution, a 67-year-old former prime minister best remembered for administering the economy during the country’s 1980s war with Iraq.

But, last week’s televised debate between Mousavi and the incumbent, Mahmoud Ahmadinejad, shed light on just how high the stakes are for the Friday election. Ahmadinejad spent much of his time defending the achievements of his hardline foreign policy: He claimed that by following the guidelines of the Islamic Revolution, Iran had weakened Israel and forced America to change its policies.

Mousavi, drawing on the authority of his personal acquaintance with Ayatollah Khomeini, who returned from exile in France in 1979 to lead the revolution and found the Islamic state, countered that Ahmadinejad had misunderstood the precepts of the revolution. It was never about needlessly antagonizing the West or about focusing on distant problems in the Holy Land at the expense of those closer to home.

Mousavi is not a perfect candidate: he bears a 20-year absence from the public stage, and neither his electoral platform, which stresses competent management over major political reform, nor his personal charisma — he mumbles and rushes through his speeches — are particularly stirring. But despite his weaknesses, he has managed to attract an unprecedented outpouring of support among the young and the middle and upper classes of the country’s cities.

Indeed, a carnival atmosphere has descended on the normally staid capital city of Tehran. Mousavi’s supporters — especially those of Iran’s baby-boom generation born in the 1980s — swarm the streets by the thousands every night, blocking major intersections as they sing impromptu campaign songs. On Monday, they constructed a human chain that spanned the entirety of the tree-lined Vali Asr, Tehran’s 12-mile-long main thoroughfare.

The fervor around Mousavi is partly a product of canny politicking — his handlers’ decision to officially adopt green, symbolic of Shiite piety and holiness, as the campaign’s official color has proved a major coup — but largely a reflection of much of the public’s distaste for the incumbent. “Competence becomes very attractive after a reign of ideology,” one student said.

Even with their minds on other issues, volunteer election canvassers for Mousavi have been content to focus their street-side pitch on issues that are designed to appeal to undecided voters, like scandalous audits by the parliament of the country’s oil income and the rate of inflation, which stood over 20 percent for much of Ahmadinejad’s term. As one smiling campaign volunteer put it, in halting English, when asked why he was for Mousavi: “Anybody but Ahmadinejad.”

Indeed, based on the arguments made by the candidates in the series of debates broadcast on Iranian public television, it seems that much more unites the challengers in the election — together with Mousavi, Karroubi, a reformist cleric, and Mohsen Rezai, a former commander of the Revolutionary Guards, are running for office — than divides them.

This likely came as little surprise to Ahmadinejad, who has had as polarizing an effect on his country as he has on the international stage. In office, Ahmadinejad hasn’t shown much inclination to win broader domestic support than the rural and urban poor who voted for him in 2005.

Over the objections of independent economic analysts, Ahmadinejad designed social services and ordered handouts for the poor that drove up the rate of inflation. And while Iranians are nearly unanimously proud of the country’s achievements in nuclear science, Ahmadinejad has earned many critics who say his preference for populist posturing over diplomatic tact has discouraged foreign investment, paved the way for international sanctions and unnecessarily made Iran a pariah state.

And though he’s said to have earned the favor of Supreme Leader Ali Khamenei, Ahmadinejad has shown little desire to curry favor with the country’s other ruling elites, swapping in hardliners at embassies, ministries and regional governments at the expensive of technocrats and reformers.

With no choice but to rely on his outsider status in the campaign, Ahmadinejad has amplified the populist class-warfare rhetoric that swept him to power four years ago. This year, he has gone so far as to take aim at broad swathes of the “ruling class” that has been in power since the 1979 revolution, making accusations that defy the Islamic Republic’s political pieties, even if they reflect many Iranians’ private grumbling.

Several prominent clerics — including influential former president Hashimi Rafsanjani — who have been targeted by the president have denied the charges of corruption and demanded that the president apologize, but Ahmadinejad has until now merely repeated his insistence that they declare the sources of their income.

The rancor between Ahmadinejad and Mousavi and between their respective supporters crested over the course of their debate. The mild-mannered Mousavi was clearly taken aback when near the end of the broadcast Ahmadinejad launched an attack against the challenger’s wife, Zahra Rahnavard, who has played a prominent role in his campaign. The president held up a picture of Rahnavard to the television cameras before accusing her of academic violations in pursuit of her doctoral degree.

Mousavi finger-shaking reply was his most impassioned of the night. He called Ahmadinejad’s methods of governance “dictatorial” and his accusations “un-Islamic.”

Many Iranians predict hard times whoever comes out on top. “If Mousavi wins, the conservatives still in power are going to push him around,” said Hamid, who works for the Mousavi campaign. This is indeed what happened during the administration of Mohammed Khatami, Iran’s previous reformist president and Mousavi’s most beloved backer.

As for the alternative? Hamid shakes his head. “The dangers of another Ahmadinejad term are obvious.”

More in our coverage of the Iranian elections:

Iranians anoint their own 'Michelle Obama'

Iranian election: A path to change or more of the same?

Contribution from the Nieman Foundation for Journalism at Harvard:

Seven Visas: Reporting from Iran 

Attempting to silence Iran’s 'Weblogistan'

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