Iranians are voting to choose their next president. The outcome is likely to be determined by several factors including turnout, the degree of fairness of the vote, the level of state interference, and the choices made by undecided and swing voters.
Here's a look at likely scenarios for how the election could play out.
If none of the six candidates running in Iran's presidential race garners 50 percent plus one of the votes, the election will head to a runoff. Most Iran observers and analysts believe this will, indeed, occur and that the runoff vote will be held on June 21.
The runoff is expected to either pit two of the three main conservative candidates -- Mohammad Baqer Qalibaf, Said Jalili, and Ali Akbar Velayati -- against each other or could feature one of the conservative hopefuls against the only moderate candidate in the race, Hassan Rohani.
Here are the most likely runoff scenarios:
Runoff Between Qalibaf And Rohani
Two opinion polls issued ahead of the vote show Qalibaf, Tehran's current mayor and a former air force commander of the Islamic Revolutionary Guards Corps (IRGC), in a tight race with Rohani, the country's former top nuclear negotiator and the only cleric in the race. The reliability of the polling data is not clear.
According to a survey issued on June 12 by the semiofficial Mehr Center for Opinion Polling, Qalibaf was leading with nearly 18 percent of the vote. Rohani came in second with almost 15 percent. Former IRGC Commander Mohsen Rezaei came in third with less than 8 percent. Velayati placed fourth.
Another poll issued on June 13 by the U.S.-based Information and Public Opinion Solution (IPOS), which conducts telephone surveys inside Iran, showed Rohani leading with just under 40 percent of the vote. Qalibaf came in second with about 25 percent.
Some observers have described Qalibaf as the most competent among the conservative presidential hopefuls, even as he lacks experience on the international stage. He appears to enjoy particular support in the capital and his campaign has made efforts to appeal to both hard-liners and to Iranian youth. Analysts say his chances of winning in the end are good.
Meanwhile, support for Rohani appears to be growing. However, analysts note that he faces a major hurdle -- that is, the clerical establishment led by Supreme Leader Ayatollah Ali Khamenei, which, they believe, does not want Rohani to win. Khamenei, they say, is determined to bring a loyalist to power.
Washington-based Iranian analyst Ali Afshari says a high turnout would increase the likelihood of a runoff between Qalibaf and Rohani.
"If more than 30 million people vote, then Rohani has the chance to be the first," Afshari says. "The withdrawal of [former Vice President Mohammad Reza] Aref from the campaign and also the strong support for him from [former President Akbar Hashemi] Rafsanjani and [former reformist President Mohammad] Khatami appear to have increased his public support. But it's still not clear to what extent. Also, some of the voters make up their mind on election day."
Afshari doubts, however, that Rohani would ultimately be allowed to win.
Runoff Between Qalibaf And Jalili
A poll issued earlier this week by the semiofficial Fars news agency said Qalibaf and Jalili, Iran's top nuclear negotiator, will face each other in a runoff. As the polling data was published by Fars, which is close to the IRGC, some observers suggest it could be one of the establishment's preferred scenarios.
Jalili is the most hard-line among the presidential candidates and is considered by some to be Khamenei’s preferred choice. Others, however, have said that perception has been inflated by Jalili's campaign.
U.S.-based Iran expert Rassol Nafisi says the Iranian leader could end up favoring whichever conservative candidate garners more public support.
"[Khamenei] has been looking at Jalili since the beginning," Nafisi says. "But it is possible that he could lean toward other candidates who have proven themselves and gained popularity."
Runoff Between Qalibaf And Velayati
Ali Akbar Velayati, a former foreign minister who advises Khamenei on international relations, is said to have a close relationship with the Iranian leader. His campaign has received the support of some lawmakers and religious institutions.
Velayati's performance during televised debates was not assessed positively and he doesn’t appear to have garnered much public support. However, some analysts believe that Khamenei does not want a president with a strong public base, meaning that Velayati could appeal to the supreme leader as unthreatening.
Runoff Between Qalibaf And Rezaei
Most analysts don't think IRGC Commander Mohsen Rezaei will make it to a second round. However, the outcomes of Iranian elections are impossible to predict. A poll published by the semiofficial Mehr news agency on June 13, which it said was conducted by a "credible" body, showed Rezai coming in a very close third behind Qalibaf and Rohani. Some reports suggest his support has been growing in the countryside.
A CONSERVATIVE CANDIDATE IS DECLARED OUTRIGHT WINNER
Analysts say that if some of the main conservative hopefuls had withdrawn from the race, this scenario could have been likely, with Qalibaf probably winning. But since all of them remain in the race, they are likely to split the public vote.
However, if the elections are tightly controlled by the establishment, then one of the main conservative candidates still could be declared the outright winner on June 14.
Analyst Afshari, a former student leader, says that for such a scenario to happen, the establishment would need to resort to massive fraud.
"This would be a situation where the elections are not normal," Afshari says. "The establishment would bring out its candidate which, according to most signs, is Said Jalili, whose views and stances completely conform to those of the supreme leader. State bodies also appear to be leaning toward him and it seems that the establishment's vote machine will be at Jalili's disposal."
For now there appear to be no signs of possible unrest. The leaders of the opposition movement, Mir Hossein Musavi and Mehdi Karrubi, remain under house arrest and many opposition activists have been jailed or otherwise silenced.
But as Karim Sadjadpour, an Iran analyst with the Carnegie Endowment for International Peace, noted in a recent interview, the political, social, and, above all, economic frustrations that compelled tens of thousands of Iranians to take to the streets in 2009 still very much exist.
"But this time around," he says, "there is no organizing principal or common cause."