President Hassan Rouhani will defend his efforts to open up Iran to the world on Friday in a final televised debate against the hardline challengers who aim to topple him in an increasingly acrimonious election next week.
Rouhani, swept into office in a landslide four years ago on promises to reduce Iran's international isolation, is seeking a second term after negotiating an agreement with world powers to curb Iran's nuclear programme in return for lifting sanctions.
Normally measured in his public speeches, he has taken the gloves off in recent days, accusing his opponents of human rights abuses and openly voicing the grievances of reformers who say they have been oppressed since the 1979 Islamic Revolution.
He faces five challengers, led by two prominent hardline frontrunners who say he has sold Iran's interests too cheaply to the West and allowed the economy to decay through mismanagement. The first round is on May 19, with a run-off a week later if no candidate wins more than 50% of the vote.
Although Iran's political system puts ultimate power in the hands of an unelected supreme leader, and all candidates are vetted by the conservative clergy, elections are nevertheless hard-fought contests that can bring dramatic change.
In two earlier, bruising debates, the main challengers, cleric Ebrahim Raisi and Tehran Mayor Mohammad Baqer Qalibaf, tore into Rouhani's economic record, arguing that he failed to bring Iranians a better life despite the lifting of sanctions.
Rouhani's biggest worry is that some of the voters who carried him to a single-round victory in 2013 will stay home, disillusioned that the lifting of sanctions has brought few economic benefits and the pace of social change has been slow.
'Crossing red lines'
Although Rouhani won more than three times as many votes as his closest challenger four years ago, he only narrowly avoided a second round with just over half the total votes. If he sheds just a bit of that support now, he could face a dangerous second round against a single opponent who unites the hardline faction.
Iran's ultimate authority Khamenei has warned the public against protests like those that broke out after the disputed election of 2009, when reformers disputed the victory of hardliner Mahmoud Ahmadinejad.
"Those who deviate from this path will be slapped in the face," Khamenei said in a televised speech on Wednesday.
The powerful Revolutionary Guards force, its affiliated volunteer Basij militia and many Friday prayer leaders have thrown their support behind Raisi, a veteran jurist whose name has also been mentioned as a future supreme leader.
