Iranians vote on Friday in a momentous election in this country of 77 million, the second-largest economy in the Middle East. Whether they vote or stay home may be the deciding factor for a reformist or a conservative victory, according to Iranian experts.
About one third of Iran's 55 million eligible voters are under 30. They tend to vote for reform-minded candidates, and a large youth turnout could steer Iran further away from the strict conservatives.
If Friday sees a large turnout among young people, "that will be good for the reformists," Mehrdad Khadir, editor of the Hope of Youth newspaper, told VICE News. "If they don't show up, that would favor the principlists."
The principlists, named for their advocacy of Islamic revolutionary principles, oppose the government of President Hassan Rouhani and distrust his openings to the West.
Reformists and centrists favor greater economic ties with Western countries and, while they want to work within the Islamic Republic's system, they also seek to lift restrictions on political organizing. While elections are relatively free and fair, a special body of Iranian clerics vets all candidates and allows only a narrow range of political debate.
On Friday Iranians go to the polls to elect members of the 290-person parliament and the 88-man Assembly of Experts, the body that will select the next Supreme Leader — a figure more powerful than the president. Current leader Ayatollah Ali Khamenei, who has the ultimate say in matters both religious and political, is 76 and reportedly in ill health.
So the elections come at a crucial time. Supporters of President Rouhani, who is hot off the successful nuclear deal with western powers and up for re-election himself next year, plans to focus on youth and other swing voters.
Western media often focus on secular, well-off Iranian youth living in north Tehran who generally back the reformists. But working-class youth from other parts of the city and the country are far more numerous and less predictable in their political views. Youth unemployment runs at 25 percent, and many young Iranians from the working-class are alienated from the system.
One of them is Farousha Fazeli, 24, who doesn't plan to vote. The elections have "nothing to do with us," she said. "The people who are going to win have already been selected."
Such alienation is common, said editor Khadir, and tends to depress voter turnout.
Among those who do vote, people who worry about the economy tend to vote reformist. But, like their parents, working class youth like the principlist view on two important matters: national security and religion. That's how Mahmoud Ahmadinejad, a working-class hero unpopular with secular, wealthier Iranians, won two terms as president: he spoke to young, poorer people.
"There are more poor people than rich people in Iran," said Foad Izadi, an associate professor at the University of Tehran. And the poor, he added, tend to be more religious. Ahmadinejad was the master of the populist, religious appeal, Khadir said.
Iranians also worry about wars and terrorism plaguing nearby countries: Iraq, Syria, Pakistan, Lebanon and Yemen. The government talked up national security in the past too, said Khadir, and "maybe back then nobody got it. But now because of ISIS and all the wars around us, people understand it better."
In that sense some principlists share similarities with Donald Trump and right-wing populist politicians in the US, according to Izadi.
"They speak their mind," he said. "They don't worry about being politically correct. [They] cater to people's fears."
The election outcome may also affect the nuclear agreement between Iran and western countries. In July last year, Iran agreed to strict limitations on its nuclear energy program in return for the lifting of harsh economic sanctions. A sector of principlists strongly opposed the accord at the time and never really accepted it.
"They continue their criticism of the accord but in a calmer manner because the Supreme Leader supports the deal," said Khadir. Principlists say Iran must be ready for the US to renege on the agreement and re-impose economic sanctions using human rights or some other excuse.
The principlists don't want the accord "to be a model that will be repeated in other areas," said Khadir. "They don't want the government to reap the political benefits of that agreement."
So far, though, the nuclear agreement has expanded support for Rouhani and his reformist allies.
Farzad Yazdoneh, a 25-year-old working-class student, said Iran's nuclear policies under the principlists were a disaster.
"Iran does not need nuclear energy because other sources are cheaper," he told VICE News. "Iran is only pursuing nuclear energy because of regional rivalry. For 14 years we were under sanctions for that."
The current political debate in Iran dates back to the disputed 2009 presidential elections. Millions of people poured into the streets to protest what they said was vote fraud. The demonstrators included young workers, clergy and others not usually associated with the opposition. They demanded major changes in Iran's constitution, which vests power in a clerical elite; others called for creating a new, secular constitution.
But after nine months, the government crushed the opposition Green Movement, and today labels any support for the demonstrations as sedition.
Today's reformists have far more modest goals; changing the constitution isn't part of the program. They do want a more open space for political organizing and the media, as well as bringing Iran back into the world economy after decades of isolation.
Principlists argue that reformist policies will encourage foreign efforts to undermine the Islamic revolution. They call for a "resistance economy" of self-reliance in preparation for a return of the American and European sanctions.
Regardless of who wins the upcoming elections, real power will remain with the Supreme Leader, the judiciary and military. Conservatives predominate in all those sectors.
But the elections will be an important indicator of popular opinion. The reformists and their allies have the modest goal of preventing a principlist victory, or at least lessening their power in the parliament and Assembly of Experts.
And that's why they are gunning for a big turnout.
"The larger the turnout is, not just youth, the reformers and people who voted for Rouhani are going to do better," said professor Izadi. After all, in 2013, "that's how they won the presidential election."
Reese Erlich received a grant from the Pulitzer Center on Crisis Reporting for his Iran coverage. He is the author of The Iran Agenda: The Real Story of US Policy and the Middle East Crisis. Follow him on Twitter: @ReeseErlich