Voters in 2005 favored the firebrand in higher percentages here than in any other city. Mr. Ahmadinejad returned the favor by making Birjand his first stop as president, lavishing the underdeveloped area, 800 miles southeast of Tehran, with projects and cash.
So no one would have been more surprised than the president himself to see the exuberant welcome given to his main challenger, Mir Hossein Mousavi, just one week before Iran's June 12 presidential election.
A raucous welcome
Mobbed from the moment he stepped out of the airport terminal on Friday night, Mr. Mousavi's supporters cast him in the role of savior-in-chief.
Two cows and a number of sheep were slaughtered to honor the former prime minister, and bloody handprints slapped onto the hood of his silver SUV, to offer a traditional form of protection.
When Mousavi stood up through the sunroof, Iranians lunged forward to touch his outstretched hands, or held up babies in search of a blessing as the motorcade passed. Smiling wanly, the reform-leaning candidate basked in what analysts say is a fresh surge.
Acolytes of the uncharismatic Mousavi call it a "green wave," after the color of the campaign, and they compare it to the level of electoral excitement that swept reformist Mohammed Khatami to a surprise landslide in 1997.
"He can be our savior," says Gholamreza Ghanbari, a veteran who lost both his legs in the Iran-Iraq War of the 1980s. He says Mousavi was "in the war with me," because he was Iran's premier at the time.
"We hope, with the people's vote, their good choice will bring a bright future and restore Iran's national dignity," says Mr. Ghanbari.
The veteran personally met Ahmadinejad twice during Birjand visits, but "nothing changed," he says.
Many manufacturing companies like his shut down. "He didn't solve the problems," he says. "He speaks very well [but] hopefully there will be change."
Mousavi faces tough challenge
Toppling Ahmadinejad, who has been in perpetual campaign mode for four years, visiting every province at least twice and spreading cash and favors to the millions of Iranians who have written letters to him, was never going to be easy.
Ahmadinejad has received frequent support from Iran's supreme religious leader, Ayatollah Sayed Ali Khamenei. And he has the quiet institutional backing of the ideological basiji militia and Revolutionary Guards, who have benefited hugely from presidential largesse.
But in Birjand, new Mousavi adherents are angry over Iran's tanking economy, the president's failure to fulfill extravagant promises, and, finally, disgust over a head-to-head debate last Wednesday in which Ahmadinejad's knifetwisting criticism exposed past regime deeds, corruption of top leaders, and even dragged Mousavi's wife into the mix.
An electrifying rally in stultifying heat
The result in Birjand was an opposition rally in which thousands of wildly cheering supporters draped in green welcomed their candidate in a sports arena with deafening cries of support and "Death to the dictator."
The political electricity was as palpable as it was unexpected, and the steaming temperature a stuffy 15 degrees hotter than the warm night outside.
"The heat in here is the heat rising toward freedom!" Mousavi told the throngs, who sweated in their physical effort of standing up, waving flags and shouting. "Birjand is known as a city of culture. They came here to buy you people with money, but they could not."
Iranian journalists who regularly travel with Mousavi say the uptick in energy at rural political rallies can almost be measured day by day in recent weeks.
Since the debate, especially, Mousavi's statements at rallies have shed their earlier polite veneer in favor of more direct attacks against Ahmadinejad.
"The people are on the scene today and they will change the atmosphere of lies and treachery, lies in the name of the Islamic Republic, lies in the name of Islam," thundered Mousavi. "The worst corruption is to lie to the people in the name of Islam. Is it correct … that you stick your head in people's private documents and private lives?"
The crowd erupted again and again. And Mousavi delivered more.
"This country was built on the blood of martyrs," he said. "Is this the message of the martyrs, that you step over everything for the interests of your group or your family?"
Breaking a long silence
And the candidate who for 20 years has kept silent in politics, to focus instead on architecture, sculpture, and painting, delivered yet more.
"You ask why you are being called a dictator," Mousavi said, referring to Ahmadinejad. "What is a dictator? Isn't it a person who stands against the law? You don't follow any rules."
When Mousavi finished, he stepped down behind the back of the podium and the crowd surged forward.
Dozens of supporters touched his white hair, rubbing their hands on his head and suit, as security guards tried to keep the candidate from being caught in the physical crush.
"Freedom," said a grandfather called Mohamad, who brought his daughter and granddaughter to the raucous event, when asked why he was there. "If there were really freedom [under Ahmadinejad], there would not be so many people here."
The last time Ahmadinejad had visited, schools and universities were closed and people told to go to his rally.
By contrast, says Mohamed, "these are real people in this place," who waited five hours to see Mousavi. "For love, we will give our lives."
"God forbid if [Ahmadinejad] becomes president again, it will become unlivable," says Mohamad Ahmadi, a business student. "He caused people's views of him to deteriorate. People are more thoughtful now."
"This is a very important day," adds student Hamidreza Jalayaeri. "We want another revolution. We have many expectation of our future leader."
Political tide shifts quickly
Those were the expectations once carried by Ahmadinejad, too, when he won so many Birjand votes. But what happened since then is lesson in how quickly Iranian politics can change.
"We have called this very fast movement the 'green wave,' and it has developed in all cities," says Mehdi Ayati, Mousavi's campaign manager here and a former Birjand member of Parliament.
"Ahmadinejad made very nice speeches, but he did not act well at all, and that is what led to this great wave against him," says Mr. Ayati. "We hope Mousavi will be a man of action, and make up for four years of Ahmadinejad and improve Iran's place in the world.
Ahmadinejad's supporters were on the streets of Birjand also, shortly after the Mousavi rally broke up.
Some 30 to 40 motorcycles with two or three young men riding each roared down the road carrying Ahmadinejad signs, not unlike the right-wing Hezbollah toughs who once attacked reformist rallies. They were flying a yellow flag of Lebanese Hezbollah militia.
A young government worker standing on the dark sidewalk as the motorcycles roared past was not impressed. Said Hossein: "Those things are not effective anymore, because people have seen the true face."