Iran's presidential election takes place on 19 May, with the incumbent, moderate Hassan Rouhani, facing a determined fight from hardline conservative Ebrahim Raisi.
The result will determine the country's future relations with the world.
Why should the rest of the world pay attention?
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Iran is a key player in the Middle East, especially due to its nuclear programme and its unwavering support for the Syrian and Iraqi governments. "World powers see Tehran both as part of the problem and the solution to the region's woes," says the BBC.
Who are the main candidates?
Rouhani is expected to be the frontrunner and the omens look promising - since 1981, all Iran’s presidents have served two terms.
However, he faces a serious threat from Raisi, who Haaretz describes as an "up-and-coming conservative firebrand”. Although a relative unknown with no ministerial experience, Raisi has solid backing from Iran's religious conservatives, who blame the current president for "selling out to the western powers", writes Bloomberg.
Polls shows Raisi commanding 27 per cent of votes, a distant second to Rouhani’s expected 42 per cent.
What are the main issues?
Outsiders tend to view Iran's politics through the prisms of human rights and the much-discussed nuclear issue, but ordinary Iranians tend to vote on the same issue which dominates elections across the globe - the economy.
Rouhani will hope to convince voters that his nuclear deal with the west, which lifted economic sanctions in exchange for restricting Tehran's nuclear programme, will offer economic benefits.
However, The Economist says his promised $50bn (£39) of foreign investment has not arrived and the country has a big unemployment problem.
Raisi’s campaign has targeted Iranians on lower incomes, arguing that the gap between rich and poor has risen since Rouhani took office and promising new monthly benefits and mass public works to create jobs.
What would a Raisi victory mean for the world?
A return to a more confrontational atmosphere with global ramifications. Raisi is a worry: the Human Rights Center of Iran says he took part in a 1988 purge of opposition members that may have killed as many as 15,000 people.
Sanam Vakil, an associate fellow at Chatham House, says Raisi would perpetuate the "siege mentality that has been passed from generation to generation, rather than trying to build bridges and bilateral relationships".
This would be particularly concerning because US President Donald Trump is an outspoken critic of the 2015 nuclear deal and has put Iran "on notice" following a ballistic missile test.
Is the election free and fair?
Yes and no. "While anyone can register as a candidate, only a chosen few are let through the gates," says the BBC.
To run for office, candidates must have the approval of the Supreme Leader Ayatollah Ali Khamenei and the hardline Guardian Council, an unelected, conservative body. A total of 1,629 potential runners were disqualified this year, including former president Mahmoud Ahmadinejad and all 137 women.
However, once the approval hurdle has been passed, the elections are for the most part free and fair, although in 2009, the regime was accused of rigging votes in favour of Ahmadinejad.
