Iranian voters will decide the fate of moderate President Hassan Rouhani and his policy of engagement with the West on Friday as he goes head-to-head with hardline cleric Ebrahim Raisi.
Rouhani has spent four years trying to pull Iran out of its global isolation, reaching a 2015 deal with world powers that ended some sanctions in exchange for curbs to its nuclear programme.
But with US President Donald Trump threatening to scrap the deal, and visiting Iran’s bitter regional rival Saudi Arabia this weekend, that policy of detente looks increasingly in jeopardy.
Raisi has agreed to stick by the nuclear accord but says Rouhani put too much trust in the West.
“We should not show any weakness in the face of the enemy,” said the 56-year-old Raisi during a televised debate.
On Wednesday, tens of thousands attended rallies by both candidates on their last day of campaigning in the northeastern city of Mashhad, which is a bastion of support for Raisi.
Rouhani defied religious authorities in the holy city, allowing a concert during his rally.
In the streets of Tehran, young Rouhani supporters wearing his campaign colours of green and purple distributed their last flyers before the polls.
The election essentially became a two-horse race after two other candidates, conservative Tehran mayor Mohammad Bagher Ghalibaf and reformist Eshaq Jahangiri, dropped out this week to boost Raisi and Rouhani respectively.
Rouhani, a 68-year-old cleric, has tried to frame the election as a choice between greater civil liberties and “extremism”, and unofficial polls still put him ahead.
Raisi was a relative unknown when he joined the race earlier this year, having mostly worked behind the scenes as a top prosecutor and recently as head of the powerful Imam Reza charitable foundation.
A close ally and former pupil of supreme leader Ayatollah Ali Khamenei, he is seen as the preferred choice of the powerful security establishment, advocating a more self-sufficient “resistance economy” rather than a reliance on foreigners.
Meanwhile, Rouhani says he needs more time to rebuild the economy, which was shattered by years of sanctions and mismanagement when he took over in 2013.